staging: sm7xxfb: rename sm712vga_setup to sm7xx_vga_setup

This patch renames sm712vga_setup to sm7xx_vga_setup. sm7xx_vga_setup
process command line options in order to get the vga parameter. This
parameter will be the lookup index to match the right vesa mode. It is
chip independent.

Signed-off-by: Javier M. Mellid <jmunhoz@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>