security/vboot: Allow UDC regardless of vboot state

When a VBOOT enabled system is used without ChromeOS it may be valid to
allow the UDC independent of the vboot state.

Provide the option to always allow UDC when CHROMEOS is not selected.

BUG=N/A
TEST=build

Change-Id: I6142c4a74ca6930457b16f62f32e1199b8baaff8
Signed-off-by: Wim Vervoorn <wvervoorn@eltan.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38403
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Frans Hendriks <fhendriks@eltan.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/security/vboot/vboot_common.c

@@ -27,6 +27,10 @@
 /* Check if it is okay to enable USB Device Controller (UDC). */
 int vboot_can_enable_udc(void)
 {
+	/* Allow UDC in all vboot modes. */
+	if (!CONFIG(CHROMEOS) && CONFIG(VBOOT_ALWAYS_ALLOW_UDC))
+		return 1;
+
 	/* Always disable if not in developer mode */
 	if (!vboot_developer_mode_enabled())
 		return 0;