Fix gemm->fname in macro

Author: ViralBShah

src/blas.jl

@@ -1488,7 +1488,7 @@ Update `C` as `alpha*A*B + beta*C` or the other three variants according to
 """
 function gemm! end
 
-for (gemm, elty) in
+for (fname, elty) in
         ((:dgemm,:Float64),
          (:sgemm,:Float32),
          (:zgemm,:ComplexF64),