manifest: libmctp: pull "library without sources" fix

Pull libmctp module update implementing fix for
"No SOURCES given to Zephyr library: modules_mctp"

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>

Author: kartben

west.yml

@@ -279,7 +279,7 @@ manifest:
       revision: bb85f7dde4195bfc0fca9e9c7c2eed0f8694203c
       path: modules/lib/liblc3
     - name: libmctp
-      revision: fa152665577a124cd957756f78fb81419c095c87
+      revision: b97860e78998551af99931ece149eeffc538bdb1
       path: modules/lib/libmctp
     - name: libmetal
       revision: 3e8781aae9d7285203118c05bc01d4eb0ca565a7