drm/amd/display: remove variable active_disp

The variable active_disp is being initialized with a value that
is never read, it is being re-assigned immediately afterwards.
Clean up the code by removing the need for variable active_disp.

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

drivers/gpu/drm/amd/display/dc/bios/bios_parser_helper.c

@@ -82,9 +82,6 @@ void bios_set_scratch_critical_state(
 uint32_t bios_get_vga_enabled_displays(
 	struct dc_bios *bios)
 {
-	uint32_t active_disp = 1;
-
-	active_disp = REG_READ(BIOS_SCRATCH_3) & 0XFFFF;
-	return active_disp;
+	return REG_READ(BIOS_SCRATCH_3) & 0XFFFF;
 }