Switch SSE2 architecture check to x86 platforms only

This allows builds on non-x86 architectures such
as ppc64el.

Bug: webrtc:14057
Signed-off-by: Timothy Pearson <tpearson@raptorcs.com>
Change-Id: Ie2c1023d2c1d041ba1d140f06af432ed9e9f7432
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/262002
Commit-Queue: Alexander Cooper <alcooper@chromium.org>
Reviewed-by: Mark Foltz <mfoltz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#36856}

AUTHORS

diff --git a/AUTHORS b/AUTHORS
index 393c1e1..68653f4 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -148,6 +148,7 @@
 Opera Software ASA <*@opera.com>
 Optical Tone Ltd <*@opticaltone.com>
 Pengutronix e.K. <*@pengutronix.de>
+Raptor Computing Systems, LLC <*@raptorcs.com>
 RingCentral, Inc. <*@ringcentral.com>
 Signal Messenger, LLC <*@signal.org>
 Sinch AB <*@sinch.com>

modules/desktop_capture/differ_block.cc

diff --git a/modules/desktop_capture/differ_block.cc b/modules/desktop_capture/differ_block.cc
index 4f0c543..54ee082 100644
--- a/modules/desktop_capture/differ_block.cc
+++ b/modules/desktop_capture/differ_block.cc
@@ -30,11 +30,7 @@
   static bool (*diff_proc)(const uint8_t*, const uint8_t*) = nullptr;
 
   if (!diff_proc) {
-#if defined(WEBRTC_ARCH_ARM_FAMILY) || defined(WEBRTC_ARCH_MIPS_FAMILY)
-    // For ARM and MIPS processors, always use C version.
-    // TODO(hclam): Implement a NEON version.
-    diff_proc = &VectorDifference_C;
-#else
+#if defined(WEBRTC_ARCH_X86_FAMILY)
     bool have_sse2 = GetCPUInfo(kSSE2) != 0;
     // For x86 processors, check if SSE2 is supported.
     if (have_sse2 && kBlockSize == 32) {
@@ -44,6 +40,10 @@
     } else {
       diff_proc = &VectorDifference_C;
     }
+#else
+    // For other processors, always use C version.
+    // TODO(hclam): Implement a NEON version.
+    diff_proc = &VectorDifference_C;
 #endif
   }