powerpc/p1010rdb: update mux config of p1010rdb board

On p1010rdb some signals are muxed for tdm/can/uart/flash.
If we don't set fsl_p1010mux:tdm_can to "can" or "tdm" explicitly,
defaultly we keep spi chip selection to spi-flash instead of to
tdm/slic and disable uart1 when not using flexcan, as well disable sdhc.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>