[ARM] 4770/1: GLAN Tank: correct physmap_flash_data width field

This patch is required, in conjunction with the patch submitted to
linux-mtd [1], to access the flash memory device in the GLAN Tank.

Without the patches, the boot log shows

physmap platform flash device: 00080000 at f0000000
...
physmap-flash physmap-flash.0: map_probe failed

whereas with the patches, the boot log shows

physmap platform flash device: 00080000 at f0000000
Found: ST M29W400DB
physmap-flash.0: Found 1 x16 devices at 0x0 in 16-bit bank
number of JEDEC chips: 1
cfi_cmdset_0002: Disabling erase-suspend-program due to code brokenness.
...
cmdlinepart partition parsing not available
Searching for RedBoot partition table in physmap-flash.0 at offset 0x70000
No RedBoot partition table detected in physmap-flash.0

The change made by this patch is required because the ST M29W400DB
flash memory chip in the GLAN Tank is used in 16 bit bus mode (~BYTE
pin is high when the board is powered on).

[1] http://lists.infradead.org/pipermail/linux-mtd/2008-January/020291.html

Signed-off-by: Gordon Farquharson <gordonfarquharson@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>