tools/bc: remove useless patch

tools/bc: remove useless patch

The remaining changes in this patch to the configure script
has no effect at all since autoreconf is used with bc
and the recent update to bc removed the need to patch
the original set of changes in order to fix building.

Remove the patch.

Removed:
 - 002-fix-libmath.patch

Fixes: abd424c3e ("tools/bc: update to 1.08.1")
Signed-off-by: Michael Pratt <mcpratt@pm.me>
Link: https://github.com/openwrt/openwrt/pull/16522
Signed-off-by: Robert Marko <robimarko@gmail.com>