This fixes a build failure for 2.6.31-rc4-rt1 (ARCH=arm, s3c2410_defconfig):

  sound/soc/s3c24xx/s3c2443-ac97.c:50: warning: type defaults to 'int' in declaration of 'DECLARE_MUTEX'
  sound/soc/s3c24xx/s3c2443-ac97.c:50: warning: parameter names (without types) in function declaration
  sound/soc/s3c24xx/s3c2443-ac97.c: In function 's3c2443_ac97_read':
  sound/soc/s3c24xx/s3c2443-ac97.c:59: error: 'ac97_mutex' undeclared (first use in this function)
  sound/soc/s3c24xx/s3c2443-ac97.c:59: error: (Each undeclared identifier is reported only once
  sound/soc/s3c24xx/s3c2443-ac97.c:59: error: for each function it appears in.)
  sound/soc/s3c24xx/s3c2443-ac97.c: In function 's3c2443_ac97_write':
  sound/soc/s3c24xx/s3c2443-ac97.c:93: error: 'ac97_mutex' undeclared (first use in this function)
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Timur Tabi <timur@freescale.com>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: alsa-devel@alsa-project.org
LKML-Reference: <1249677761-19470-2-git-send-email-u.kleine-koenig@pengutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>