drm/radeon: Fix wrong boolean operator

This error is reported by cppcheck:
drivers/gpu/drm/radeon/radeon_encoders.c:1066: warning: Mutual exclusion over || always evaluates to true. Did you intend to use && instead?

It looks like cppcheck is correct, so fix this. No test was run.

Cc: David Airlie <airlied@linux.ie>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_encoders.c

@@ -1063,7 +1063,7 @@ atombios_set_edp_panel_power(struct drm_connector *connector, int action)
 	if (!ASIC_IS_DCE4(rdev))
 		return;
 
-	if ((action != ATOM_TRANSMITTER_ACTION_POWER_ON) ||
+	if ((action != ATOM_TRANSMITTER_ACTION_POWER_ON) &&
 	    (action != ATOM_TRANSMITTER_ACTION_POWER_OFF))
 		return;