[ARM] pxa: make cpu_is_pxa2* macros more consistent

1. add a CPUID table in the comment

2. make cpu_is_pxa25x() true for PXA210/250/255/26x

3. PXA210 is treated as PXA25x, all related code modified to
   reflect this

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-pxa/pxa25x.c b/arch/arm/mach-pxa/pxa25x.c
index 1be490d..a3a6aff 100644
--- a/arch/arm/mach-pxa/pxa25x.c
+++ b/arch/arm/mach-pxa/pxa25x.c
@@ -348,7 +348,7 @@
 {
 	int i, ret = 0;
 
-	if (cpu_is_pxa21x() || cpu_is_pxa25x()) {
+	if (cpu_is_pxa25x()) {
 
 		reset_status = RCSR;