[FIX] Limit applicability of is_1stconv logic for JIT FP32/BF16 AVX512 Convolution

Author: dmitrygo

src/cpu/x64/jit_avx512_common_conv_kernel.cpp

@@ -75,10 +75,7 @@ inline status_t init_tag(format_tag_t &tag, memory_desc_t &md,
 }
 
 inline bool is_1stconv(const jit_conv_conf_t &jcp) {
-    if (mayiuse(avx512_core))
-        return (jcp.ic < 16 && jcp.ngroups == 1);
-    else
-        return one_of(jcp.ic, 1, 3);
+    return one_of(jcp.ic, 1, 3);
 }
 
 inline bool is_ow_threading_on(const jit_conv_conf_t &jcp) {

src/cpu/x64/jit_avx512_core_bf16_conv_kernel.cpp

@@ -91,7 +91,7 @@ inline bool is_1stconv(const jit_conv_conf_t &jcp) {
                     * nstl::max(jcp.typesize_in, jcp.typesize_out) * jcp.id
                     * jcp.ih * jcp.iw
             < INT_MAX;
-    return jcp.ic < 16 && jcp.ngroups == 1 && no_big_offt;
+    return one_of(jcp.ic, 1, 3) && jcp.ngroups == 1 && no_big_offt;
 }
 } // namespace