Fix an incorrect identifier

Summary:
EIEIO is not a correct declaration and breaks the build under Debian HURD.
Instead, E_IEIO is used.

//
http://www.gnu.org/software/libc/manual/html_node/Reserved-Names.html
Some additional classes of identifier names are reserved for future
extensions to the C language or the POSIX.1 environment. While using
these names for your own purposes right now might not cause a problem,
they do raise the possibility of conflict with future versions of the C
or POSIX standards, so you should avoid these names.
...
Names beginning with a capital ‘E’ followed a digit or uppercase letter
may be used for additional error code names. See Error Reporting.//

Reported here:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=776965
And patch wrote by Svante Signell 
With this patch, LLVM, Clang & LLDB build under Debian HURD:
https://buildd.debian.org/status/fetch.php?pkg=llvm-toolchain-3.6&arch=hurd-i386&ver=1%3A3.6~%2Brc2-2&stamp=1423040039

Reviewers: hfinkel

Reviewed By: hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7437

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228331 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPCInstrInfo.td

@@ -3137,7 +3137,8 @@ def ISYNC : XLForm_2_ext<19, 150, 0, 0, 0, (outs), (ins),
 def ICBI : XForm_1a<31, 982, (outs), (ins memrr:$src),
                     "icbi $src", IIC_LdStICBI, []>;
 
-def EIEIO : XForm_24_eieio<31, 854, (outs), (ins),
+// We used to have EIEIO as value but E[0-9A-Z] is a reserved name
+def EnforceIEIO : XForm_24_eieio<31, 854, (outs), (ins),
                            "eieio", IIC_LdStLoad, []>;
 
 def WAIT : XForm_24_sync<31, 62, (outs), (ins i32imm:$L),