nvfx: Remove unnecessary headers.

src/gallium/drivers/nvfx/nvfx_miptree.c

 #include "nouveau/nouveau_screen.h"
 #include "nvfx_screen.h"
 #include "nvfx_resource.h"
-#include "nvfx_transfer.h"
-#include "nv04_2d.h"
 
 static void
 nvfx_miptree_choose_format(struct nvfx_miptree *mt)

src/gallium/drivers/nvfx/nvfx_resource.c

 #include "pipe/p_context.h"
 #include "util/u_staging.h"
 #include "nvfx_resource.h"
-#include "nvfx_transfer.h"
 #include "nouveau/nouveau_screen.h"
 
 static unsigned int

src/gallium/drivers/nvfx/nvfx_surface.c

 #include "util/u_math.h"
 #include "util/u_memory.h"
 #include "util/u_pack_color.h"
-#include "util/u_rect.h"
 #include "util/u_blitter.h"
 
 #include "nouveau/nouveau_winsys.h"