[arm] Clean up handling of usat.

src/arm/assembler-arm.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions
 // are met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 1720 matching lines @@
 }
 
 
 // Saturating instructions.
 
 // Unsigned saturate.
 void Assembler::usat(Register dst,
                      int satpos,
                      const Operand& src,
                      Condition cond) {
-  // v6 and above.
-  DCHECK(CpuFeatures::IsSupported(ARMv7));
   DCHECK(!dst.is(pc) && !src.rm_.is(pc));
   DCHECK((satpos >= 0) && (satpos <= 31));
   DCHECK((src.shift_op_ == ASR) || (src.shift_op_ == LSL));
   DCHECK(src.rs_.is(no_reg));
 
   int sh = 0;
   if (src.shift_op_ == ASR) {
       sh = 1;
   }
 
@@ skipping 2511 matching lines @@
     DCHECK(is_uint12(offset));
     instr_at_put(pc, SetLdrRegisterImmediateOffset(instr, offset));
   }
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM