mmc/dwmmc: use bounce buffer for data exchange between CPU and MMC controller

mmc/dwmmc: use bounce buffer for data exchange between CPU and MMC controller

Bounce buffer implementation takes care of proper data buffer alignemt
and correct flush/invalidation of data cache at once so we no longer
depend on input data variety and make sure CPU and MMC controller deal
with expected data in case of enabled data cache.

Bounce buffer requires to add its definition (CONFIG_BOUNCE_BUFFER) in
board configuration, otherwise corresponding library won't be compiled
and linker will fail to build resulting executable.

Difference since v1 - fixed compile-time warning with type casting to
"void *":

Slight edit to remove UTF8 characters in the commit message.

Acked-by: Jaehoon Chung <[email protected]>
Tested-by: Jaehoon Chung <[email protected]>
Acked-by: Pantelis Antoniou <[email protected]>
====
passing argument 2 of 'bounce_buffer_start' discards 'const' qualifier
from pointer target type
====

Signed-off-by: Alexey Brodkin <[email protected]>
Cc: Mischa Jonker <[email protected]>
Cc: Alim Akhtar <[email protected]>
Cc: Rajeshwari Shinde <[email protected]>
Cc: Jaehoon Chung <[email protected]>
Cc: Amar <[email protected]>
Cc: Kyungmin Park <[email protected]>
Cc: Minkyu Kang <[email protected]>
Cc: Simon Glass <[email protected]>
Cc: Pantelis Antoniou <[email protected]>
Cc: Andy Fleming <[email protected]>