The commit 1e0af58b51 ("pmci: Move MCTP into the PMCI subsys") changes
'mctp' directory adding to unconditionally, which will cause:
CMake Warning at ./zephyrproject/zephyr/CMakeLists.txt:1022 (message):
No SOURCES given to Zephyr library: subsys__pmci__mctp
Excluding target from build.
Signed-off-by: Haiyue Wang <haiyuewa@163.com>
9c9c080b68