soc: Synchronize RESET event and lpi ops in legacy driver

Race condition is observed during ADSP SSR
when LPI pinctrl receives the SERVICE DOWN
event and lpi gpio read or write is executed.
Synchronize these functions using lock.

Change-Id: Ie80c41e260b4b572c1c3ede8a2a58a3a0332fe7d
Signed-off-by: Soumya Managoli <smanag@codeaurora.org>