[x86] Fix a capitalization that I failed to save in my editor before

landing the patch. =/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336986 91177308-0d34-0410-b5e6-96231b3b80d8

Author: chandlerc

test/CodeGen/X86/flags-copy-lowering.mir

@@ -914,7 +914,7 @@ body:             |
     successors: %bb.1, %bb.9
 
     ; Outer loop latch. Note that we cannot have EFLAGS live-in here as that
-    ; Immediately require PHIs.
+    ; immediately require PHIs.
     CMP64rr %0, %1, implicit-def $eflags
     JE_1 %bb.1, implicit $eflags
     JMP_1 %bb.9