Move immintrin/arm_neon includes to where they are used.

src/opts/SkSwizzler_opts.h

Index: src/opts/SkSwizzler_opts.h
diff --git a/src/opts/SkSwizzler_opts.h b/src/opts/SkSwizzler_opts.h
index 15eec3a355a1bee38f28008c7ef0a1fc36ccafb5..a22e1450200926eac5d29264d192bc68d4027733 100644
--- a/src/opts/SkSwizzler_opts.h
+++ b/src/opts/SkSwizzler_opts.h
@@ -10,6 +10,12 @@
 
 #include "SkColorPriv.h"
 
+#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSSE3
+    #include <immintrin.h>
+#elif defined(SK_ARM_HAS_NEON)
+    #include <arm_neon.h>
+#endif
+
 namespace SK_OPTS_NS {
 
 static void RGBA_to_rgbA_portable(uint32_t* dst, const void* vsrc, int count) {