serial: imx: bit &/| confusion

Since UCR1_UARTEN is defined 1, the port was always treated as enabled.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Oskar Schirmer <os@emlix.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Fabian Godehardt <fg@emlix.com>
Cc: Daniel Glöckner <dg@emlix.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>