Revert "scsi: ufs: Increase ah8 idle to 10ms"

There is some power impact seen with autohibern8 idle
timer value of 10ms. Hence reverting back the autohiber8 timer
value back to 5ms.

This reverts commit ef3f24dd.

Change-Id: Ic2f97e6f53e1711a869c9617e15c06e53d1e2e33
Signed-off-by: Nitin Rawat <nitirawa@codeaurora.org>