[ARM] 2787/2: PXA27x low power modes support

Patch from Todd Poynor

Add symbols for PXA2xx PWRMODE register M field that selects low-power
mode, replace unadorned constants.  Honor power mode parameter of
pxa_cpu_suspend(mode), no longer force to 3 (sleep).  Full Deep Sleep
low-power mode support for PXA27x is pending generic PM interfaces to
select more than 2 suspend-to-RAM-style power modes, but this is
expected soon. This can be hardcoded in the meantime by replacing the
pxa_cpu_suspend() parameter value.  From David Burrage and Todd Poynor.
Try #2 removes one of the register copies and moves the code to save the
pxa_cpu_suspend parameter to immediately surround the call that requires
the parameter value be preserved.

Signed-off-by: Todd Poynor <tpoynor@mvista.com>
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-pxa/standby.S b/arch/arm/mach-pxa/standby.S
index 8a3f27b..6f6dbbd 100644
--- a/arch/arm/mach-pxa/standby.S
+++ b/arch/arm/mach-pxa/standby.S
@@ -21,7 +21,7 @@
 ENTRY(pxa_cpu_standby)
 	ldr	r0, =PSSR
 	mov	r1, #(PSSR_PH | PSSR_STS)
-	mov	r2, #2
+	mov	r2, #PWRMODE_STANDBY
 	mov	r3, #UNCACHED_PHYS_0	@ Read mem context in.
 	ldr	ip, [r3]
 	b	1f