There is a 12MB unused region in our memory map between the vmalloc and
fixmap areas. This became unused with commit e9da6e99, confirmed
with commit 64d3b6a3.

We also have a 8MB guard area before the vmalloc area.  With the default
240MB vmalloc area size and the current VMALLOC_END definition, that
means the end of low memory ends up at 0xef800000 which is unfortunate
for 768MB machines where 8MB of RAM is lost to himem.

Let's move VMALLOC_END to 0xff800000 so the guard area won't chop the
top of the 768MB low memory area while keeping the default vmalloc area
size unchanged and still preserving a gap between the vmalloc and fixmap
areas.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>