OMAP3: l3: fix for "irq 10: nobody cared" message

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: Omar Ramirez Luna <omar.ramirez@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>