mmc: card: set timeout value for sanitize operation

During secure discard, the sanitize operation is started
without any timeout value set, which result in a timeout
of 10 seconds applied at the SDHCi driver.

But since the sanitize operation was started after secure
discard was issued, it could take longer than 10 seconds.
So setting a timeout of 30 seconds based on testing done
so far.

CRs-Fixed: 567327
Change-Id: I27e3c9743ca17c151d478b8772649c366a2fd8f3
Signed-off-by: Krishna Konda <kkonda@codeaurora.org>