wireless: Convert mwifiex/pcie to dev_pm_ops from legacy pm_ops

Convert the mwifiex/pci driver to use dev_pm_ops for power management and
remove Legacy PM handling. This change re-uses existing suspend and resume
interfaces for dev_pm_ops, and changes CONFIG_PM ifdefs to CONFIG_PM_SLEEP
as the driver does not support run-time PM.

Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
Acked-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>