[X86] Remove usesCustomInserter from MWAITX_SAVE_EBX and MWAITX_SAVE_RBX. NFC

These are now emitted by a CustomInserter rather than using a custom
inserter themselves.

Author: topperc

llvm/lib/Target/X86/X86InstrCompiler.td

@@ -901,8 +901,7 @@ def LCMPXCHG16B_SAVE_RBX :
 // cf comment for LCMPXCHG8B_SAVE_EBX.
 let Defs = [ECX, EAX, EBX, EFLAGS], Uses = [ECX, EAX, EBX],
     Predicates = [HasMWAITX], SchedRW = [WriteSystem],
-    isCodeGenOnly = 1, isPseudo = 1, Constraints = "$ebx_save = $dst",
-    usesCustomInserter = 1 in {
+    isCodeGenOnly = 1, isPseudo = 1, Constraints = "$ebx_save = $dst" in {
 def MWAITX_SAVE_EBX :
     I<0, Pseudo, (outs GR32:$dst),
       (ins GR32:$ebx_input, GR32:$ebx_save),
@@ -912,8 +911,7 @@ def MWAITX_SAVE_EBX :
 // Same as MWAITX_SAVE_EBX but for the case where RBX is the base pointer.
 let Defs = [ECX, EAX, EBX, EFLAGS], Uses = [ECX, EAX, EBX],
     Predicates = [HasMWAITX], SchedRW = [WriteSystem],
-    isCodeGenOnly = 1, isPseudo = 1, Constraints = "$rbx_save = $dst",
-    usesCustomInserter = 1 in {
+    isCodeGenOnly = 1, isPseudo = 1, Constraints = "$rbx_save = $dst" in {
 def MWAITX_SAVE_RBX :
     I<0, Pseudo, (outs GR64:$dst),
       (ins GR32:$ebx_input, GR64:$rbx_save),