Compile failure on systems without AVX2, fix included

openair1/PHY/TOOLS/cmult_sv.c fails to compile when AVX2 is not defined. On the test system, I have: C_FLAGS_PROCESSOR is -msse4.1 -mpclmul -mssse3

The issue occurs with tag 2022.w37b, but it is likely a bit older.

Patch to fix the issue in this file:

diff --git a/openair1/PHY/TOOLS/cmult_sv.c b/openair1/PHY/TOOLS/cmult_sv.c
index a596446a44..bac0f97f9e 100644
--- a/openair1/PHY/TOOLS/cmult_sv.c
+++ b/openair1/PHY/TOOLS/cmult_sv.c
@@ -218,7 +218,9 @@ void rotate_cpx_vector(c16_t *x,
       xd+=4;
       y_128+=1;
     }
+#ifdef __AVX2__
   }
+#endif
 }
 
 #ifdef MAIN
'''