video: samsung: Fix build error with gcc-4.6+

drivers/video/samsung/s3cfb.h:234:36: error: inlining failed in call to
always_inline 'get_fimd_global': function body not available

Change-Id: I1bccc25b6ef04ae86461ef2a82858155ed096d72
Signed-off-by: Dongjin Kim <tobetter@gmail.com>