Revert "add KPATCH_WARN_*_LINE macros"

This reverts commit 57b51d0bdce53a928bde6c3370fcd0f06cfa0ad4.

Probably no longer needed now that we have KPATCH_IGNORE_FUNCTION and
KPATCH_IGNORE_SECTION.
Merge pull request #334 from jpoimboe/revert-warn-macros

Revert "add KPATCH_WARN_*_LINE macros"