Fix OPENSSL_NO_ASM definition in bazel.

https://boringssl-review.googlesource.com/c/boringssl/+/51265 broke
Linux and macOS platforms on architectures where we don't build
assembly. OPENSSL_NO_ASM needs to match the assembly selector.

While I'm here, remove the OPENSSL_C11_ATOMIC comment. We autodetect
atomics these days, so the flag is only useful if you want to force it.

Change-Id: I1f20f7577b5ca7e208dc90fb46a93b20da864ec5
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/51305
Reviewed-by: Piotr Sikora <piotrsikora@google.com>
Reviewed-by: Adam Langley <agl@google.com>

util/BUILD.toplevel

@@ -80,11 +80,6 @@ posix_copts = [
     "-Wwrite-strings",
     "-Wshadow",
     "-fno-common",
-
-    # Modern build environments should be able to set this to use atomic
-    # operations for reference counting rather than locks. However, it's
-    # known not to work on some Android builds.
-    # "-DOPENSSL_C11_ATOMIC",
 ]
 
 linux_copts = posix_copts + [
@@ -97,13 +92,11 @@ linux_copts = posix_copts + [
 boringssl_copts = select({
     "@platforms//os:linux": linux_copts,
     "@platforms//os:macos": posix_copts,
-    "@platforms//os:windows": [
-        "-DWIN32_LEAN_AND_MEAN",
-        "-DOPENSSL_NO_ASM",
-    ],
-    "//conditions:default": ["-DOPENSSL_NO_ASM"],
+    "@platforms//os:windows": ["-DWIN32_LEAN_AND_MEAN"],
+    "//conditions:default": [],
 })
 
+# These selects must be kept in sync.
 crypto_sources_asm = select({
     ":linux_aarch64": crypto_sources_linux_aarch64,
     ":linux_ppc64le": crypto_sources_linux_ppc64le,
@@ -111,6 +104,13 @@ crypto_sources_asm = select({
     ":macos_x86_64": crypto_sources_mac_x86_64,
     "//conditions:default": [],
 })
+boringssl_copts += select({
+    ":linux_aarch64": [],
+    ":linux_ppc64le": [],
+    ":linux_x86_64": [],
+    ":macos_x86_64": [],
+    "//conditions:default": ["-DOPENSSL_NO_ASM"],
+})
 
 # For C targets only (not C++), compile with C11 support.
 posix_copts_c11 = [