avcodec/ac3dec: Put CONFIG* first in if()

This may fix build failures with EAC3 disabled and is more consistent
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/ac3dec.c

@@ -601,7 +601,7 @@ static void decode_transform_coeffs_ch(AC3DecodeContext *s, int blk, int ch,
         /* if AHT is used, mantissas for all blocks are encoded in the first
            block of the frame. */
         int bin;
-        if (!blk && CONFIG_EAC3_DECODER)
+        if (CONFIG_EAC3_DECODER && !blk)
             ff_eac3_decode_transform_coeffs_aht_ch(s, ch);
         for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) {
             s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin];
@@ -1352,7 +1352,7 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
     }
 
     /* apply spectral extension to high frequency bins */
-    if (s->spx_in_use && CONFIG_EAC3_DECODER) {
+    if (CONFIG_EAC3_DECODER && s->spx_in_use) {
         ff_eac3_apply_spectral_extension(s);
     }