Revert "mmc: sdhci: Fix voltage switch delay"

This reverts commit 940b7740 which is
commit c981cdfb upstream.

It breaks the Android ABI so revert it for now.  If this is needed in
the future, it can be brought back in an ABI safe way.

Bug: 161946584
Change-Id: Ia5d24c9adcb06166546c42810759b9193d4eaceb
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>