ARM: 8891/1: EDAC: armada_xp: Add support for more SoCs

The Armada 38x and other integrated SoCs use a reduced pin count so the
width of the SDRAM interface is smaller than the Armada XP SoCs. This
means that the definition of "full" and "half" width is reduced from
64/32 to 32/16.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>