drivers/mfd/max8998.c: fix pointer-integer size mismatch warning in max8998_i2c_get_driver_data()

Fix up the following pointer-integer size mismatch warning in
max8998_i2c_get_driver_data():

	drivers/mfd/max8998.c: In function 'max8998_i2c_get_driver_data':
	drivers/mfd/max8998.c:178:10: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
		return (int)match->data;
		       ^

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Tomasz Figa <t.figa@samsung.com>
Cc: Mark Brown <broonie@linaro.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>