uboot-imx

mx25: Fix imx_get_perclk()

imx_get_perclk() used the AHB clock as the clock source for all PER
clocks, but the USB PLL output can also be a PER clock source if the
corresponding PER CLK MUX bit is set in CCM.MCR.

Signed-off-by: Benoît Thébaudeau <benoit@wsystem.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>