linux-imx

fsi: scom: Add mutex around FSI2PIB accesses

Otherwise, multiple clients can open the driver and attempt
to access the PIB at the same time, thus clobbering each other
in the process.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>