include: uapi: Add hack for BCM multi-path TCP

Broadcom's kernel conditionally adds additional enum constants
TCP_RST_WAIT and BPF_TCP_RST_WAIT. TCP_* and BPF_TCP_* enums have to be
in sync which is checked by a static assert during build. The enums are
guarded by an ifdef depending on a config option in Broadcom's kernel.

Broadcom option BUILD_MPTCP, which controls the corresponding kernel
option, is unconditionally enabled for all profiles, so we can enable
the ifdef unconditionally as a workaround.

Signed-off-by: Andreas Gnau <andreas.gnau@iopsys.eu>