omap2_mcspi fixes + cleanups

Initial updates for McSPI driver:

- bug fixes:
* handle byte-wide tx pio correctly for multiple bytes
* cleanup workqueue on module exit
* allow modular build (and rmmod)
* request_mem_region
* remove wrongly exported driver symbol

- cleanup:
* remove needless debug strings from object file
* remove needless init and exit sections from object file
* remove superfluous get/put of spi_master
* fix whitespace and indentation bugs
* fix line-too-long bugs
* use spi_master_*() calls not class_*() calls
* use dev_*() messaging not printk

Combined with the next patch, this gives around a 10% shrink to the driver footprint, improves correctness, and helps it get ready to merge upstream.

---
 drivers/spi/Kconfig       |    2 
 drivers/spi/omap2_mcspi.c |  254 ++++++++++++++++++++++++----------------------
 2 files changed, 134 insertions(+), 122 deletions(-)

@@ -134,7 +134,7 @@ config SPI_OMAP_UWIRE
 	  This hooks up to the MicroWire controller on OMAP1 chips.
 
 config SPI_OMAP24XX
-	bool "McSPI driver for OMAP24xx"
+	tristate "McSPI driver for OMAP24xx"
 	depends on SPI_MASTER && ARCH_OMAP24XX
 	help
 	  SPI master controller for OMAP24xx McSPI modules.