fbdev/ps3fb: Use struct fb_info.screen_buffer

Use info->screen_buffer when reading and writing framebuffers in
system memory. It's the correct pointer for this address space.

The struct fb_info has a union to store the framebuffer memory. This can
either be info->screen_base if the framebuffer is stored in I/O memory,
or info->screen_buffer if the framebuffer is stored in system memory.

As the driver operates on the latter address space, it is wrong to use
.screen_base and .screen_buffer must be used instead. This also gets
rid of casting needed due to not using the correct data type.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428122452.4856-10-tzimmermann@suse.de

drivers/video/fbdev/ps3fb.c

@@ -650,7 +650,7 @@ static int ps3fb_set_par(struct fb_info *info)
 	}
 
 	/* Clear XDR frame buffer memory */
-	memset((void __force *)info->screen_base, 0, info->fix.smem_len);
+	memset(info->screen_buffer, 0, info->fix.smem_len);
 
 	/* Clear DDR frame buffer memory */
 	lines = vmode->yres * par->num_frames;
@@ -1139,7 +1139,7 @@ static int ps3fb_probe(struct ps3_system_bus_device *dev)
 	 * memory
 	 */
 	fb_start = ps3fb_videomemory.address + GPU_FB_START;
-	info->screen_base = (char __force __iomem *)fb_start;
+	info->screen_buffer = fb_start;
 	info->fix.smem_start = __pa(fb_start);
 	info->fix.smem_len = ps3fb_videomemory.size - GPU_FB_START;