mmc: Kconfig: Add FSL_ESDHC_USE_PERIPHERAL_CLK option

NXP fsl_esdhc controller supports two reference clocks:
platform clock and peripheral clock
Peripheral clock can provide higher clock frequency
which is required to be used for tuning of SD UHS mode
and eMMC HS200/HS400 modes.

Peripheral clock is enabled by default by defining config
option FSL_ESDHC_USE_PERIPHERAL_CLK if eMMC HS200/HS400 modes
are supported.

Signed-off-by: Yinbo Zhu <yinbo.zhu@nxp.com>
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>