mmc: Add a prototype for board_mmc_init()

Fixes the following sparse warning:

wandboard.c:137:5: warning: symbol 'board_mmc_init' was not declared. Should it be static?

Cc: Pantelis Antoniou <panto@antoniou-consulting.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
1 file changed