MLK-22296-3 misc: fxls8471_i2c: Fix build warning when CONFIG_PM_SLEEP=n

MLK-22296-3 misc: fxls8471_i2c: Fix build warning when CONFIG_PM_SLEEP=n

Fix build warning when CONFIG_PM_SLEEP=n, the warning message is:
drivers/input/misc/fxls8471_i2c.c:77:12: warning: ‘fxls8471_i2c_resume’ defined but not used [-Wunused-function]
 static int fxls8471_i2c_resume(struct device *dev)
            ^~~~~~~~~~~~~~~~~~~
drivers/input/misc/fxls8471_i2c.c:71:12: warning: ‘fxls8471_i2c_suspend’ defined but not used [-Wunused-function]
 static int fxls8471_i2c_suspend(struct device *dev)
            ^~~~~~~~~~~~~~~~~~~~

Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>