ARM: 8637/1: Adjust memory boundaries after reservations

adjust_lowmem_bounds is responsible for setting up the boundary for
lowmem/highmem. This needs to be setup before memblock reservations can
occur. At the time memblock reservations can occur, memory can also be
removed from the system. The lowmem/highmem boundary and end of memory
may be affected by this but it is currently not recalculated. On some
systems this may be harmless, on others this may result in incorrect
ranges being passed to the main memory allocator. Correct this by
recalculating the lowmem/highmem boundary after all reservations have
been made.

Tested-by: Magnus Lilja <lilja.magnus@gmail.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>