Replace the x86 XGETBV instruction with its opcode bytes

This is a new instruction, present on the SandyBridge architecture and
later. Some older assemblers do not support it and produce:

  {standard input}:225:no such instruction: `xgetbv'

The use of this instruction is protected by a CPUID check (function 1,
ECX bit 27), so we only run it in processors that do support it.

Change-Id: Ife7500c0deaab9539074835a4511e8c19602608e
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>

src/corelib/tools/qsimd.cpp

@@ -244,7 +244,7 @@ static void xgetbv(int in, uint &eax, uint &edx)
     eax = result;
     edx = result >> 32;
 #elif defined(Q_CC_GNU)
-    asm ("xgetbv"
+    asm (".byte 0x0F, 0x01, 0xD0" // xgetbv instruction
         : "=a" (eax), "=d" (edx)
         : "c" (in));
 #endif