memtest fails when a reserved sdram region is at the bank start at
address 0. This patch supports the exclusion of memory region at
the bank start.
Tested on P2020RDB and DA923RC, qemuarm versatilepb.
Signed-off-by: Renaud Barbier <renaud.barbier@ge.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>