Implement new CPU detection using cpuid, cpuidex plan9 instructions from klauspost/cpuid project, remove C code

pkg/cpu/cpu_amd64.s

@@ -0,0 +1,27 @@
+// Copyright (c) 2015 Klaus Post, released under MIT License. See LICENSE file.
+//
+// See https://github.com/klauspost/cpuid/blob/master/LICENSE
+//
+// Using this inside Minio with modifications
+//
+
+// func cpuid(op uint32) (eax, ebx, ecx, edx uint32)
+TEXT ·cpuid(SB),7,$0
+        MOVL op+0(FP),AX
+        CPUID
+        MOVL AX,eax+8(FP)
+        MOVL BX,ebx+12(FP)
+        MOVL CX,ecx+16(FP)
+        MOVL DX,edx+20(FP)
+        RET
+
+// func cpuidex(op, op2 uint32) (eax, ebx, ecx, edx uint32)
+TEXT ·cpuidex(SB),7,$0
+        MOVL op+0(FP),AX
+        MOVL op2+4(FP),CX
+        CPUID
+        MOVL AX,eax+8(FP)
+        MOVL BX,ebx+12(FP)
+        MOVL CX,ecx+16(FP)
+        MOVL DX,edx+20(FP)
+        RET