ARM: 8433/1: add a VMSPLIT_3G_OPT config option

Mimicking the same config option on x86, this allows for 1GB systems to
have their RAM entirely mapped as low memory.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -1469,6 +1469,8 @@ choice
 
 	config VMSPLIT_3G
 		bool "3G/1G user/kernel split"
+	config VMSPLIT_3G_OPT
+		bool "3G/1G user/kernel split (for full 1G low memory)"
 	config VMSPLIT_2G
 		bool "2G/2G user/kernel split"
 	config VMSPLIT_1G
@@ -1480,6 +1482,7 @@ config PAGE_OFFSET
 	default PHYS_OFFSET if !MMU
 	default 0x40000000 if VMSPLIT_1G
 	default 0x80000000 if VMSPLIT_2G
+	default 0xB0000000 if VMSPLIT_3G_OPT
 	default 0xC0000000
 
 config NR_CPUS