If gapdummy.c is compiled with -fcf-protection=branch, clang 13

If gapdummy.c is compiled with -fcf-protection=branch, clang 13
creates and additional section .note.gnu.property.  With that the
linker creates a section .plt in gap.o.  In the end, a .plt section
is also present in the kernel.  There it does not make sense.  As
a quick fix explcitly disable cf protection when compiling gapdummy.c
to gapdummy.o.  There is no code to protect anyway.
OK deraadt@