V4L/DVB (10243): em28xx: fix compile warning

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/em28xx/em28xx.h

@@ -321,7 +321,7 @@ enum em28xx_aout {
 	EM28XX_AOUT_PCM_PHONE	= 7 << 8,
 };
 
-static int ac97_return_record_select(int a_out)
+static inline int ac97_return_record_select(int a_out)
 {
 	return (a_out & 0x700) >> 8;
 }