Fix warning arch/arm/plat-omap/dsp/dsp_ctl_core.c: In function 'dsp_ctl_core_open': arch/arm/plat-omap/dsp/dsp_ctl_core.c:46: warning: ignoring return value of 'mutex_lock_interruptible', declared with attribute warn_unused_result Signed-off-by: Dirk Behme