Make sure the mmc_spi driver can build without CONFIG_BLOCK.
Issue noted by "Avuton Olrich" <avuton@gmail.com> and randconfig.

While that won't be a common configuration, sometimes embedded
boards use SDIO to interface WLAN or Bluetooth chips (vs some
parallel interface), and don't provide an MMC/SD socket for use
with flash memory cards.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is the latest version of the MMC-over-SPI support.  It works
on 2.6.23-rc2 plus git-mmc (from rc1-mm2), along with the preceding
patches which teach the rest of the MMC stack about SPI.

The main issue of note is that sometimes cards need to be power cycled
to recover after certain faults.  Also, it may sometimes be necessary
to disable CRCs.  ("modprobe mmc_core use_spi_crc=n")
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: mikael.starvik@axis.com,
Cc: Hans-Peter Nilsson <hp@axis.com>
Cc: Jan Nikitenko <jan.nikitenko@gmail.com>
Cc: Mike Lavender <mike@steroidmicros.com>
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>