[ARM] pxa: simplify DMA register definitions

1. DRCMRxx is no longer recommended, use DRCMR(xx) instead, and
   pass DRCMR index by "struct resource" if possible

2. DCSRxx, DDADRxx, DSADRxx, DTADRxx, DCMDxx is never used, use
   DCSR(), DDADR(), DSADR(), DTADR(), DCMD() instead

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Acked-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>