staging: mt7621-mmc: Remove single statement macro msdc_irq_restore()

This patch removes the macro msdc_irq_restore() and replaces its
usage with call to the function called in the macro definition.
Issue found by checkpatch.

Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>