serial: samsung: Fix build error

drivers/tty/serial/samsung.c: In function 's3c24xx_serial_init':
drivers/tty/serial/samsung.c:1237: error: lvalue required as unary '&' operand

Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>