ENGR00119432 MX35 system can't re-boot up when SD/MMC boot is used.

Do not disable the eSDHC clk on MX35 3DS board,
since SYSTEM can't boot up after the reset key
is pressed when the SD/MMC boot mode is used.
The root cause is that the ROM code don't ensure
the SD/MMC clk is running when boot system.

Signed-off-by: Richard Zhu <r65037@freescale.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>