Minor issue in lwipopts.h in macro expansion in parameters (cosmetic
change: it expands correctly but doesn't pass the expected argument)
Fix lwip thread safety issue in tests: dhcp server should be started and
stopped only in lwip context/thread. Without this fix, the test would
fail if `CONFIG_LWIP_CHECK_THREAD_SAFETY=y`
Adds CONFIG_LWIP_TCPIP_CORE_LOCKING=y to some mqtt example tests (the
same configs as used in v5.1)