Rev 1.5 microsoms include eMMC support on-board.  Add a microsom include
file which can be used to add support for this.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>