Yangbo Lu authored Dec 19, 2019 and Peng Fan committed Jan 16, 2020

The QorIQ eSDHC controller supports two reference clocks. They are
platform clock and periperhal clock. The global variable sdhc_clk
has already been used for platform clock.
This patch is to add another global variable sdhc_per_clk for
periperhal clock, which provides higher frequency and is required
to be used for SD UHS and eMMC HS200/HS400 speed modes.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>