ARM: 6652/1: ep93xx: correct the end address of the AC97 memory resource

The last register is at offset 0xa8 making the resource end to be 0xac - 1
instead of 0xb0 - 1.

Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>