ARM: LPC32xx: Remove wrong re-initialization of MMC clock register

This patch fixes a bug, (wrongfully) resetting the value of
LPC32XX_CLKPWR_MS_CTRL back to its initial contents (after careful setup). This
was discovered only with a board/bootloader combination (EA3250) where the
contents of the respective register wasn't already at the correct value on
Linux boot.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Acked-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>