fbdev: Don't re-validate info->state in fb_ops implementations

The file-op entry points fb_read() and fb_write() verify that
info->state has been set to FBINFO_STATE_RUNNING. Remove the same
test from the implementations of struct fb_ops.{fb_read,fb_write}.

v2:
	* also remove test from ivtvfb, braodsheetfb, hecubafb and
	  metronomefb (Geert)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Helge Deller <deller@gmx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428122452.4856-17-tzimmermann@suse.de