If an error occurs in the L3 on any other initiator than MPU,
the interrupt goes unhandled given that the 'base' register
was calculated with the initialized err_source value (which
coincidentally points to MPU) and not with the actual source
of the error.

Removed parenthesis that are not needed for the touched lines.
Signed-off-by: NOmar Ramirez Luna <omar.ramirez@ti.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>