ARM: OMAP2+: Fix location for select PM_GENERIC_DOMAINS

I accidentally misplaced select PM_GENERIC_DOMAINS, it should be
selected for all the SoCs instead.

Fixes: 58cbff02 ("soc: ti: omap-prm: Add basic power domain support")
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/Kconfig

@@ -7,7 +7,6 @@ config ARCH_OMAP2
 	depends on ARCH_MULTI_V6
 	select ARCH_OMAP2PLUS
 	select CPU_V6
-	select PM_GENERIC_DOMAINS if PM
 	select SOC_HAS_OMAP2_SDRC
 
 config ARCH_OMAP3
@@ -106,6 +105,7 @@ config ARCH_OMAP2PLUS
 	select OMAP_DM_TIMER
 	select OMAP_GPMC
 	select PINCTRL
+	select PM_GENERIC_DOMAINS if PM
 	select RESET_CONTROLLER
 	select SOC_BUS
 	select TI_SYSC