pci 2 0 0 call rs780_enable.
pcs 3 0 0 call rs780_gfx_3_init.
auto_gen2_speed_change has been added on rs780_enable, but not rs780_gfx_3_init.
added it into rs780_gfx_3_init now.
Change-Id: I7fe060e1c3df7790ecfceb1fdf1b7569bff24701
Signed-off-by: QiaoChong <qiaochong@loongson.cn>