Implement "fastboot flash" for eMMC

This series implements the "fastboot flash" command for eMMC devices. It supports both raw and sparse images.

NOTES:
- the support for the "fastboot flash" command is enabled with CONFIG_FASTBOOT_FLASH
- the support for eMMC is enabled with CONFIG_FASTBOOT_FLASH_MMC_DEV
- (future) the support for NAND would be enabled with CONFIG_FASTBOOT_FLASH_NAND(???)

This has been tested on ARMv7.

----

This series depends on:

   http://patchwork.ozlabs.org/patch/382443/ (to 382446)

Changes in v6:
- printf() to error()
- fix spelling
- remove excess braces

Changes in v5:
- use the common/aboot.c for the "sparse format" handling

Changes in v4:
- rearranged this patchset so that "sparse_format.h" can be dropped (if we cannot resolve the copyright/licensing issues)
- update mmc_get_dev(...) to get_dev("mmc",....)
- update printf() to puts() where applicable
- update debug string as per feedback
- rearranged "sparse format" support in this patchset, in order to isolate...

Changes in v3:
- remove most references to 'mmc',
which leaves only one mmc specific function: mmc_get_dev()

Changes in v2:
- split large function into three
- improved handling of response messages
- additional partition size checking when writing sparse image
- update README.android-fastboot file
- new in v2

Steve Rae (4):
usb/gadget: fastboot: add eMMC support for flash command usb/gadget: fastboot: add support for flash command usb/gadget: fastboot: minor cleanup
usb/gadget: fastboot: implement sparse format

  README                          | 10 +++++
  common/Makefile                 |  6 +++
  common/cmd_fastboot.c           |  7 ++--
  common/fb_mmc.c                 | 92 +++++++++++++++++++++++++++++++++++++++++
  doc/README.android-fastboot     |  5 ++-
  drivers/usb/gadget/f_fastboot.c | 44 ++++++++++++++++++--
  include/fb_mmc.h                |  8 ++++
  7 files changed, 163 insertions(+), 9 deletions(-)

create mode 100644 common/fb_mmc.c
create mode 100644 include/fb_mmc.h