mtd: mxc_nand: remove unused variable

This fixes:

	drivers/mtd/nand/mxc_nand.c: In function 'mxcnd_resume':
	drivers/mtd/nand/mxc_nand.c:901: warning: unused variable 'host'

Removing this variable was missed in 9c14b153.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>