DMA: PL330: Add missing static storage class specifier

Fixes the following sparse warning:
drivers/dma/pl330.c:2542:5: warning: symbol 'add_desc' was not declared. Should it be static?

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
1 file changed