[MTD] [NOR] fix startup lock when using multiple nor flash chips

Taken from http://bugzilla.kernel.org/show_bug.cgi?id=9829

I found and solved the problem, at line 115 of drivers/mtd/chips/gen_probe.c
(kernel 2.6.24): mapsize value must be calculated in bytes, not in long.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>