FSL/eSDHC: enable the clock to detect the SD card

FSL/eSDHC: enable the clock to detect the SD card

For FSL low-end processors (VVN2.2), in order to detect the SD card,
we should enable PEREN, HCKEN and IPGEN to enable the clock.
Otherwise, after booting the u-boot, and then inserting the SD card,
the SD card can't be detected.
For SDHC VVN2.3 IP, these bits are reserved, and SDCLKEN is used.
And when accessing to these reserved bit, no any impact happened.

Signed-off-by: Jerry Huang <Chang-Ming.Huang@freescale.com>
CC: Andy Fleming <afleming@gmail.com>
CC: Marek Vasut <marex@denx.de>
Signed-off-by: Andy Fleming <afleming@freescale.com>