video: da8xx-fb: fb_set_par support

v1: original from Afzal Mohammed <afzal@ti.com>
fb_set_par helps in runtime configuration of lcd controller like
changing resolution, pixel clock etc. (eg. using fbset utility)

Reconfigure lcd controller based on information passed by framework.
Enable raster back if it was already enabled.

As fb_set_par would get invoked indirectly from probe via fb_set_var,
remove existing lcdc initialization in probe and do lcdc reset in
probe so that reset happens only at the begining.

v2:  changes from Darren Etheridge <detheridge@ti.com>
	remove unnecessary conditional branch where we attempt to disable
	something that we already checked to see if it was disabled.

Signed-off-by: Darren Etheridge <detheridge@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>