build_variables.bzl: split PATTERN_SRCS from PORTABLE_KERNELS_SRCS (#13353)

Making the structure in this file mirror buck's worldview more closely
when it makes sense. #8268

Differential Revision:
[D80187448](https://our.internmc.facebook.com/intern/diff/D80187448)

Author: swolchok

kernels/portable/cpu/pattern/targets.bzl

@@ -1,3 +1,4 @@
+load("@fbsource//xplat/executorch/build:build_variables.bzl", "PATTERN_SRCS")
 load("@fbsource//xplat/executorch/build:runtime_wrapper.bzl", "runtime")
 
 def define_common_targets():
@@ -49,11 +50,7 @@ def define_common_targets():
 
     runtime.cxx_library(
         name = "pattern",
-        srcs = [
-            "unary_ufunc_realhbbf16_to_bool.cpp",
-            "unary_ufunc_realhbbf16_to_floathbf16.cpp",
-            "unary_ufunc_realhbf16.cpp",
-        ],
+        srcs = PATTERN_SRCS,
         exported_headers = [
             "pattern.h",
         ],

shim_et/xplat/executorch/build/build_variables.bzl

@@ -61,6 +61,12 @@ EXECUTORCH_CORE_SRCS = sorted([
     "schema/extended_header.cpp",
 ] + ["runtime/executor/" + x for x in PROGRAM_NO_PRIM_OPS_SRCS] + ["runtime/platform/" + x for x in PLATFORM_SRCS])
 
+PATTERN_SRCS = [
+    "unary_ufunc_realhbbf16_to_bool.cpp",
+    "unary_ufunc_realhbbf16_to_floathbf16.cpp",
+    "unary_ufunc_realhbf16.cpp",
+]
+
 PORTABLE_KERNELS_SRCS = [
     "kernels/portable/cpu/op__clone_dim_order.cpp",
     "kernels/portable/cpu/op__empty_dim_order.cpp",
@@ -227,10 +233,7 @@ PORTABLE_KERNELS_SRCS = [
     "kernels/portable/cpu/op_view_copy.cpp",
     "kernels/portable/cpu/op_where.cpp",
     "kernels/portable/cpu/op_zeros.cpp",
-    "kernels/portable/cpu/pattern/unary_ufunc_realhbbf16_to_bool.cpp",
-    "kernels/portable/cpu/pattern/unary_ufunc_realhbbf16_to_floathbf16.cpp",
-    "kernels/portable/cpu/pattern/unary_ufunc_realhbf16.cpp",
-]
+] + ["kernels/portable/cpu/pattern/" + x for x in PATTERN_SRCS]
 
 KERNELS_UTIL_ALL_DEPS_SRCS = [
     "kernels/portable/cpu/util/activation_ops_util.cpp",