ARM: kirkwood: enable HIGHMEM in defconfig

The Kirkwood-based OpenBlocks A7 platform has 1 GB of memory. To make
use of this memory completely, enabling HIGHMEM is needed, so we
enable it by default in the kirkwood_defconfig.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NJason Cooper <jason@lakedaemon.net>

arch/arm/configs/kirkwood_defconfig

@@ -27,6 +27,7 @@ CONFIG_PCI_MVEBU=y
 CONFIG_PREEMPT=y
 CONFIG_AEABI=y
 # CONFIG_OABI_COMPAT is not set
+CONFIG_HIGHMEM=y
 CONFIG_ZBOOT_ROM_TEXT=0x0
 CONFIG_ZBOOT_ROM_BSS=0x0
 CONFIG_CPU_FREQ=y