scsi: ufs: Try to save power mode change and UIC cmd completion timeout

Use the uic_cmd->cmd_active as a flag to track the lifecycle of an UIC cmd.
The flag is set before send the UIC cmd and cleared after the completion is
raised in IRQ handler. For a power mode change operation, including hibern8
enter/exit, the flag is cleared only after hba->uic_async_done completion
is raised. When completion timeout happens, if the flag is cleared, instead
of returning timeout error, simply ignore it.

Change-Id: Ie3cd6ae6221a44619925fb2cf78136a5617fdd5d
Signed-off-by: Can Guo <cang@codeaurora.org>