mmc: core: Implement software CRCs control

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>
sync: Implement FSync control

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>
ramdisk: Import Nexus 7 (2013) 5.0.1 ramdisk

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>