[ARM] pxa: separate definitions from pxa-regs.h and remove it finally

The remaining registers are separated into:

   - <mach/regs-ost.h>
   - <mach/regs-rtc.h>
   - <mach/regs-intc.h>

and then we can remove pxa-regs.h completely. Instead of #include this
file, let's:

1. include the specific <mach/regs-*.h> with care (if that's absolutely
   necessary)

2. define the registers in the driver, make cleanly defined API to expose
   the register access to external with sufficient reason

Signed-off-by: Eric Miao <eric.miao@marvell.com>
diff --git a/drivers/rtc/rtc-sa1100.c b/drivers/rtc/rtc-sa1100.c
index d26a5f8..4f247e4 100644
--- a/drivers/rtc/rtc-sa1100.c
+++ b/drivers/rtc/rtc-sa1100.c
@@ -35,7 +35,8 @@
 #include <asm/irq.h>
 
 #ifdef CONFIG_ARCH_PXA
-#include <mach/pxa-regs.h>
+#include <mach/regs-rtc.h>
+#include <mach/regs-ost.h>
 #endif
 
 #define RTC_DEF_DIVIDER		32768 - 1