Revert "x86/sbrdsp: remove unnecessary sign extend instruction in apply_noise_main"

This reverts commit 24bb7db4.

noise has to after all be sign extended, not zero extended, on tests
other than checkasm.
Fixes most aac tests broken by the now reverted commit.

libavcodec/x86/sbrdsp.asm

@@ -382,7 +382,8 @@ apply_noise_main:
 %else
     DEFINE_ARGS Y, s_m, q_filt, noise, kx, count
 %endif
-    dec    noised
+    movsxdifnidn    noiseq, noised
+    dec    noiseq
     shl    countd, 2
 %ifdef PIC
     lea NOISE_TABLE, [sbr_noise_table]