misc: panel: Remove reference to misc device support

As of commit 7c5763b8 ("drivers: misc: Remove MISC_DEVICES
config option"), misc device support no longer needs to be enabled
manually.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>