ARM: SAMSUNG: Remove unnecessary code for dma

This patch removes the usage of DMACH_DT_PROP and dt_dmach_prop
from dma code as the new generic dma dt binding support has been
added.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>