mmc: host: add support to allow SANITIZE operation

SANITIZE is an operation performed by the storage device and its purpose
is to delete its unmap memory regions.
This change adds support for the SANITIZE capability.

Change-Id: I58b647fb576c694aaa16c1e827d0784d4a5b4456
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
Signed-off-by: Pavan Anamula <pavana@codeaurora.org>