[ARM] 3290/1: Fix the FIFO size detection

Patch from Catalin Marinas

AACI reports TX FIFO full after the first write to it if the AC97 is not
enabled. This patch enables the AC97 probing before the check for the TX
FIFO size. The patch also adds a warning if the TX FIFO size is not
multiple of 16.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>