tests: drivers: sdhc: setup SDHC IO before test

Rather than relying to the alphanumeric test ordering implemented in
ZTEST to ensure certain tests run first, setup the SDHC IO properties to
known good values before starting any of the tests. This allows the SDHC
tests to run in any order, rather than needing certain tests to run
first.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>