mmc: block: flush request requeue after timeout

On some eMMC cards cache flush is taking longer than 30 sec timeout
after HPI issued and -EIO reported to the upper layers. This may result
into journaling issues as flush calls are issued by the file system
joulrnaling code.

This change increases flush cache timeout to 90 sec, in case of timeout
occurs, after HPI issued, flush request re-queued to the block layer queue
to execute it later and keep journaling logic valid.

CRs-fixed: 545528
Change-Id: I1e968c07056062fd9c8e14e5bc3e62b3b4b99c64
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>