linux-phytec-ti

kbuild: Make DEBUG_SECTION_MISMATCH selectable, but not on by default

CONFIG_DEBUG_SECTION_MISMATCH has also runtime effects due to the
-fno-inline-functions-called-once compiler flag, so forcing it on
everyone is not a good idea.

Signed-off-by: Michal Marek <mmarek@suse.cz>