dnn: vec_neon: avoid redefinition of vcvtnq_s32_f32

clang exposes this intrinsic even in 32-bit mode, if targeting >= armv8,
whereas gcc does not, see:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95399
Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>
1 file changed