Revert "mmc: Disable MMC_CAP_ERASE for all drivers"

This reverts commit 13acd9f89d25c7ebd56ab65d59dcf6a5c6f895d2.

Change-Id: Ie939cc6bf7337dad180f8d7e24662782184ec043
mmc: card: Skip secure erase on MoviNAND; causes unrecoverable corruption.

commit 3550ccdb9d8d350e526b809bf3dd92b550a74fe1 upstream.

For several MoviNAND eMMC parts, there are known issues with secure
erase and secure trim.  For these specific MoviNAND devices, we skip
these operations.

Specifically, there is a bug in the eMMC firmware that causes
unrecoverable corruption when the MMC is erased with MMC_CAP_ERASE
enabled.

References:

http://forum.xda-developers.com/showthread.php?t=1644364
https://plus.google.com/111398485184813224730/posts/21pTYfTsCkB#111398485184813224730/posts/21pTYfTsCkB

Change-Id: Iaa6509716b0ad7930e9b3a97a9f8576abf1d91c0