mfd: rtsx: Optimize card detect flow

commit 504decc0 upstream.

1. Schedule card detect work at the end of the ISR
2. Callback function ops->cd_deglitch may delay for a period of time.
It is not proper to call this callback when local irq disabled.
3. Card detect flow can't be executed in parallel with other card reader
operations, so it's better to be protected by mutex.

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Cc: Tim Gardner <rtg.canonical@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>