i386: Move Intel intrinsics head files to <immintrin.h>

i386: Move Intel intrinsics head files to <immintrin.h>

According to Intel Intrinsics Guide:

https://software.intel.com/sites/landingpage/IntrinsicsGuide/

Intel intrinsics should be available by including <immintrin.h>.  This
patch moves remaining Intel intrinsics head files from <x86intrin.h> to
<immintrin.h>.

	PR target/71659
	* config/i386/adxintrin.h: Just check _IMMINTRIN_H_INCLUDED.
	* config/i386/clflushoptintrin.h: Check _IMMINTRIN_H_INCLUDED
	instead of _X86INTRIN_H_INCLUDED.
	* onfig/i386/clwbintrin.h: Likewise.
	* config/i386/pkuintrin.h: Likewise.
	* config/i386/prfchwintrin.h: Likewise.
	* config/i386/rdseedintrin.h: Likewise.
	* config/i386/wbnoinvdintrin.h: Likewise.
	* config/i386/xsavecintrin.h: Likewise.
	* config/i386/xsavesintrin.h: Likewise.
	* config/i386/fxsrintrin.h: Enable _IMMINTRIN_H_INCLUDED check.
	* config/i386/xsaveintrin.h: Likewise.
	* config/i386/xsaveoptintrin.h: Likewise.
	* config/i386/x86intrin.h: Move "#include" <rdseedintrin.h>,
	<prfchwintrin.h>, <fxsrintrin.h>, <xsaveintrin.h>,
	<xsaveoptintrin.h>, <adxintrin.h>, <clwbintrin.h>,
	<clflushoptintrin.h>, <xsavesintrin.h>, <xsavecintrin.h>,
	<wbnoinvdintrin.h> and <pkuintrin.h> to ...
	* config/i386/immintrin.h: Here.

From-SVN: r268113