mmc: remove MMC bus legacy suspend/resume method

mmc: remove MMC bus legacy suspend/resume method

MMC bus is using legacy suspend/resume method, which is not compatible if
runtime pm callbacks are used. In this scenario, MMC bus suspend/resume
callbacks cannot be called when system entering S3. So change to use the
new defined dev_pm_ops for system sleeping mode.

Tested on AM335x Platform. Solves major issue/crash reported at
http://www.mail-archive.com/[email protected]/msg65425.html

Signed-off-by: Chuanxiao Dong <[email protected]>
Tested-by: Hebbar, Gururaja <[email protected]>
Acked-by: Linus Walleij <[email protected]>
Acked-by: Ulf Hansson <[email protected]>
Signed-off-by: Chris Ball <[email protected]>