Change OPENSSL_cpuid_setup to reserve more extended feature space.

Copy of openssl change https://git.openssl.org/gitweb/?p=openssl.git;h=d6ee8f3dc4414cd97bd63b801f8644f0ff8a1f17

OPENSSL_ia32cap: reserve for new extensions.
Change-Id: I96b43c82ba6568bae848449972d3ad9d20f6d063
Reviewed-on: https://boringssl-review.googlesource.com/27564
Reviewed-by: David Benjamin <davidben@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/include/openssl/cpu.h b/include/openssl/cpu.h
index dd95ddc..bb847f9 100644
--- a/include/openssl/cpu.h
+++ b/include/openssl/cpu.h
@@ -86,7 +86,8 @@
 //     Bit 11 is used to indicate AMD XOP support, not SDBG
 //   Index 2:
 //     EBX for CPUID where EAX = 7
-//   Index 3 is set to zero.
+//   Index 3:
+//     ECX for CPUID where EAX = 7
 //
 // Note: the CPUID bits are pre-adjusted for the OSXSAVE bit and the YMM and XMM
 // bits in XCR0, so it is not necessary to check those.