mmc: fsl_esdhc_imx: replace most #ifdefs by IS_ENABLED()

[ fsl_esdhc commit 52faec31 ]

Make the code cleaner and drop the old-style #ifdef constructs where it is
possible.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Sean Anderson <sean.anderson@seco.com>