ARM: 5940/2: ARM: MMCI: remove custom DBG macro and printk

This removes the custom DBG macro in favor of the in-kernel
dev_dbg() macro. Probably a leftover from a time when dev_dbg()
didn't yet exist. Also remove a printk() in favor of dev_err().

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>