lcd, pxafb: move the pxafb to drivers/video

lcd, pxafb: move the pxafb to drivers/video

Since the lcd code was compiled unconditionally for pxa also add
CONFIG_PXA_LCD to the boards using this framebuffer. Since
driver/video contains video and lcd drivers, add lcd to the name
to make clear it belongs to common/lcd.c.

cc: Anatolij Gustschin <agust@denx.de>
cc: Cliff Brake <cliff.brake@gmail.com>
cc: Marek Vasut <marek.vasut@gmail.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>