dmaengine: sun6i: depends on RESET_CONTROLLER

Fixes a compilation error when RESET_CONTROLLER is not enabled in the
configuration.

drivers/dma/sun6i-dma.c: In function 'sun6i_dma_probe':
drivers/dma/sun6i-dma.c:911:2: error: implicit declaration of function 'devm_reset_control_get' [-Werror=implicit-function-declaration]

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>