esdhc/usdhc: Fix warning when CONFIG_SYS_FSL_ESDHC_USE_PIO is not set

In 71689776 we made calls to check_and_invalidate_dcache_range()
conditional on !CONFIG_SYS_FSL_ESDHC_USE_PIO.  Only define this function
in this case as well.

Signed-off-by: Tom Rini <trini@ti.com>