uboot-imx

Clean up INIT_RAM options

The L2_INIT_RAM option was unused, and recent changes to the TLB code
meant that the INIT_RAM TLBs weren't being cleared out.  In order to reduce
the amount of mapped space attached to nothing, we change things so the TLBs
get cleared.

Signed-off-by: Andy Fleming <afleming@freescale.com>