drivers/i2s_sam_ssc.c: enable cache support

Enable cache operations before starting a DMA operation if the CPU has a
cache. All the support was already in place, it just needs to be
enabled.

With the previous commits, it allows the I2S tests to pass on a SAM E70
Xplained board with the CPU cache enabled.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
1 file changed