arm: mach-omap2: devices: fix omap3_l3_init() return value

Fix the return value for the successful case.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>