scsi: ufs: core: Introduce a new clock_gating lock

scsi: ufs: core: Introduce a new clock_gating lock

Introduce a new clock gating lock to serialize access to some of the clock
gating members instead of the host_lock.

While at it, simplify the code with the guard() macro and co for automatic
cleanup of the new lock. There are some explicit
spin_lock_irqsave()/spin_unlock_irqrestore() snaking instances I left
behind because I couldn't make heads or tails of it.

Additionally, move the trace_ufshcd_clk_gating() call from inside the
region protected by the lock as it doesn't needs protection.

Signed-off-by: Avri Altman <avri.altman@wdc.com>
Link: https://lore.kernel.org/r/20241124070808.194860-4-avri.altman@wdc.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>