In the non highmem case, if two memory banks of 1GB each are provided,
the second bank would evade suppression since its virtual base would
be 0.  Fix this by disallowing any memory bank which virtual base
address is found to be lower than PAGE_OFFSET.
Reported-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>