remoteproc: Add dependency to HAS_DMA

Remoteproc relies on HAS_DMA, add this dependency in Kconfig.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>