mb/google/brox/var/lotso: Remove STORAGE_UNKNOWN fw_config option

With `probe unprovisioned` fw_config rule, there is no need to define an
explicit STORAGE_UNKNOWN option. Hence remove it.

BUG=None
TEST=Build Lotso FW image.

Change-Id: Ia170a6e006cb51e95fbaf3efe1106ca907165eca
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84094
Reviewed-by: Nick Vaccaro <nvaccaro@google.com>
Reviewed-by: Bob Moragues <moragues@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/brox/variants/lotso/overridetree.cb b/src/mainboard/google/brox/variants/lotso/overridetree.cb
index 6876b64..e81848d 100644
--- a/src/mainboard/google/brox/variants/lotso/overridetree.cb
+++ b/src/mainboard/google/brox/variants/lotso/overridetree.cb
@@ -5,7 +5,6 @@
 		option RETIMER_JHL8040		2
 	end
 	field STORAGE 2 3
-		option STORAGE_UNKNOWN		0
 		option STORAGE_UFS		1
 		option STORAGE_NVME		2
 	end
@@ -331,7 +330,6 @@
 				.clk_src = 0,
 				.flags = PCIE_RP_LTR | PCIE_RP_AER,
 			}"
-			probe STORAGE STORAGE_UNKNOWN
 			probe STORAGE STORAGE_NVME
 			probe unprovisioned
 		end
@@ -381,12 +379,10 @@
 			chip drivers/intel/ish
 				device generic 0 alias ish_conf on end
 			end
-			probe STORAGE STORAGE_UNKNOWN
 			probe STORAGE STORAGE_UFS
 			probe unprovisioned
 		end
 		device ref ufs on
-			probe STORAGE STORAGE_UNKNOWN
 			probe STORAGE STORAGE_UFS
 			probe unprovisioned
 		end