ARM: at91: move "select SRAM" under SOC_AT91SAM9 and SOC_SAMA5

To simply the PM config the CONFIG_AT91_SLOW_CLOCK option will be removed,
so move "select SRAM" from under AT91_SLOW_CLOCK, add "select SRAM if PM"
under SOC_AT91SAM9 and SOC_SAMA5

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Tested-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/mach-at91/Kconfig

@@ -24,6 +24,7 @@ config SOC_SAMA5
 	select GENERIC_CLOCKEVENTS
 	select MEMORY
 	select ATMEL_SDRAMC
+	select SRAM if PM
 
 menu "Atmel AT91 System-on-Chip"
 
@@ -80,6 +81,7 @@ config SOC_AT91RM9200
 	select CPU_ARM920T
 	select GENERIC_CLOCKEVENTS
 	select HAVE_AT91_USB_CLK
+	select SRAM if PM
 
 config SOC_AT91SAM9
 	bool "AT91SAM9"
@@ -93,6 +95,7 @@ config SOC_AT91SAM9
 	select HAVE_AT91_UTMI
 	select HAVE_FB_ATMEL
 	select MEMORY
+	select SRAM if PM
 	help
 	  Select this if you are using one of those Atmel SoC:
 	    AT91SAM9260
@@ -117,7 +120,6 @@ comment "AT91 Feature Selections"
 
 config AT91_SLOW_CLOCK
 	bool "Suspend-to-RAM disables main oscillator"
-	select SRAM
 	depends on SUSPEND
 	help
 	  Select this if you want Suspend-to-RAM to save the most power