ARM: 6418/1: ux500: rename DB8500 DMA event line macros

Change the DMA event line macros to have the name of the SoC.  Also,
have the event line number encoded in the macro since on DB5500 several
event lines are present at multiple alternate numbers.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>