vf_select: Drop a debug av_log with an unchecked double to enum conversion

CC: libav-stable@libav.org
Merge commit 'a8d803a320fb08b3ad5db4fffc79abd401206905'

* commit 'a8d803a320fb08b3ad5db4fffc79abd401206905':
  vf_select: Drop a debug av_log with an unchecked double to enum conversion

Conflicts:
	libavfilter/f_select.c

Not merged, see next commit for the bugfix

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avfilter/f_select: avoid using doubles for equals checks and casts to enums

This might silence some warnings.

Issue found from: a8d803a320fb08b3ad5db4fffc79abd401206905
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>