Update the MPC8349E-mITX, MPC8313E-RDB, and MPC837XE-RDB board files to upload
the Vitesse VSC7385 firmware.  Changed CONFIG_VSC7385 to CONFIG_VSC7385_ENET.
Cleaned up the board header files to make selecting the VSC7385 easier to
control.

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