ARM: OMAP3+: SmartReflex: fix error handling

Fix the code to correctly use IS_ERR and PTR_ERR on the return
values pointers

Reported-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>