drm/amd/display: Return value of function

Added return value check hpd_enable

Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Denis Arefev <arefev@swemel.ru>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_link_encoder.c

@@ -1645,7 +1645,7 @@ void dce110_link_encoder_enable_hpd(struct link_encoder *enc)
 	uint32_t hpd_enable = 0;
 	uint32_t value = dm_read_reg(ctx, addr);
 
-	get_reg_field_value(hpd_enable, DC_HPD_CONTROL, DC_HPD_EN);
+	hpd_enable = get_reg_field_value(hpd_enable, DC_HPD_CONTROL, DC_HPD_EN);
 
 	if (hpd_enable == 0)
 		set_reg_field_value(value, 1, DC_HPD_CONTROL, DC_HPD_EN);