uboot-imx

lib_ppc: make board_add_ram_info weak

platforms wishing to display RAM diagnostics in addition to size,
can do so, on one line, in their own board_add_ram_info()
implementation.

this consequently eliminates CONFIG_ADD_RAM_INFO.

Thanks to Stefan for the hint.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>