swresample/arm: remove unintentional relocation.

swresample/arm: remove unintentional relocation.

Branch to global symbol results in reference to PLT, and when compiling
for THUMB-2 - in a R_ARM_THM_JUMP19 relocation. Some linkers don't
support this relocation (ld.gold), while others can end up truncating
the relocation to fit (ld.bfd).

Convert this branch through PLT into a direct branch that the assembler
can resolve locally.

See https://github.com/android-ndk/ndk/issues/337 for background.

The current workaround is to disable neon during gstreamer build,
which is not optimal and can be reverted after this patch:
https://github.com/freedesktop/gstreamer-cerbero/commit/41556c415739fbc3a72c7eaee7e70a565b719b2f

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>