Add dev_warn_probe() and improve error handling in Rockchip SPI drivers

This is a small series that introduces dev_warn_probe() function, which produces warnings on failed resource acquisitions, and improves error handling in the probe paths of Rockchip SPI drivers, by using functions dev_err_probe() and dev_warn_probe() properly in multiple places.

This series also performs a bunch of small, rather trivial code cleanups, to make the code neater and a bit easier to read.

Changes in v3:
- Fixed a couple of rather embarrassing issues in patch 4/5 pointed out by the kernel test robot, [7] one of them using the va_copy() workaround approach already established in the commit 3fbcf75bb41a ("efi/printf: Factor out width/precision parsing"), but all this really made me think how didn't I notice those issues myself before sending the patches, which perhaps slipped by because I didn't take the specifics of x86_64 into account :/
- Added a somewhat lengthy comment to patch 4/5, to explain the newly introduced va_copy() workaround, partially reusing the comment found in the above-mentioned commit 3fbcf75bb41a
- Added underscores to the name of the "worker" function in patch 4/5, to additionally emphasize its internal nature
- Adjusted some of the variable names in patch 4/5 a bit to use what are seemingly more commonly used names

Changes in v2:
- Collected three Reviewed-by tags from Heiko [1][2][3]
- Dropped patch 3/5, [4] as suggested by Mark, [5] improved the check to use dev_err_probe() and folded that into new patch 5/5
- Added new patch 4/5 that introduces function dev_warn_probe() that produces warnings in probe paths, to avoid the promotion of logged messages from warnings to errors, as noted by Heiko [6]
- Adjusted the description of the series and of the individual patches a bit to reflect the changes, where appropriate

Link to v2: https://lore.kernel.org/linux-rockchip/[email protected]/T/#u
Link to v1: https://lore.kernel.org/linux-rockchip/[email protected]/T/#u

[1] https://lore.kernel.org/linux-rockchip/6085918.31tnzDBltd@phil/
[2] https://lore.kernel.org/linux-rockchip/2285557.3ZeAukHxDK@phil/
[3] https://lore.kernel.org/linux-rockchip/10409403.0AQdONaE2F@phil/
[4] https://lore.kernel.org/linux-rockchip/ce2e7f90e62b15adc2bed1f53122ad39c3a9b5ac.1727337732.git.dsimic@manjaro.org/
[5] https://lore.kernel.org/linux-rockchip/[email protected]/
[6] https://lore.kernel.org/linux-rockchip/6673004.tM3a2QDmDi@phil/
[7] https://lore.kernel.org/linux-rockchip/[email protected]/

Dragan Simic (5):
spi: rockchip: Perform trivial code cleanups
spi: rockchip-sfc: Perform trivial code cleanups
spi: rockchip-sfc: Use dev_err_probe() in the probe path driver core: Add device probe log helper dev_warn_probe()
spi: rockchip: Use dev_{err,warn}_probe() in the probe path

 drivers/base/core.c            | 129 ++++++++++++++++++++++++++-------
 drivers/spi/spi-rockchip-sfc.c |  21 ++----
 drivers/spi/spi-rockchip.c     |  55 +++++++-------
 include/linux/dev_printk.h     |   1 +
 4 files changed, 135 insertions(+), 71 deletions(-)