AMDGPU: Fix typo in argument allocation error message

Author: arsenm

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

@@ -2459,7 +2459,7 @@ void SITargetLowering::allocateSpecialInputVGPRsFixed(
     SIMachineFunctionInfo &Info) const {
   Register Reg = CCInfo.AllocateReg(AMDGPU::VGPR31);
   if (!Reg)
-    report_fatal_error("failed to allocated VGPR for implicit arguments");
+    report_fatal_error("failed to allocate VGPR for implicit arguments");
 
   const unsigned Mask = 0x3ff;
   Info.setWorkItemIDX(ArgDescriptor::createRegister(Reg, Mask));