drm/amd/display: Remove redundant initialization of variable eng_id

The variable eng_id is being initialized with a value that is never
read, it is being re-assigned on the next statment. The assignment
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_link_enc_cfg.c

@@ -305,7 +305,7 @@ struct link_encoder *link_enc_cfg_get_next_avail_link_enc(
 	const struct dc_state *state)
 {
 	struct link_encoder *link_enc = NULL;
-	enum engine_id eng_id = ENGINE_ID_UNKNOWN;
+	enum engine_id eng_id;
 
 	eng_id = find_first_avail_link_enc(dc->ctx, state);
 	if (eng_id != ENGINE_ID_UNKNOWN)