The correct order is: NULL check before dereference

This was a guaranteed NULL dereference with debugging enabled since
rs5c372_sysfs_show_osc() does actually pass NULL...

Spotted by the Coverity checker.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>