video_core: Remove unnecessary enum class casting in logging messages

fmt now automatically prints the numeric value of an enum class member
by default, so we don't need to use casts any more.

Reduces the line noise a bit.

src/video_core/shader/decode/arithmetic.cpp

@@ -110,8 +110,7 @@ u32 ShaderIR::DecodeArithmetic(NodeBlock& bb, u32 pc) {
             case SubOp::Sqrt:
                 return Operation(OperationCode::FSqrt, PRECISE, op_a);
             default:
-                UNIMPLEMENTED_MSG("Unhandled MUFU sub op={0:x}",
-                                  static_cast<unsigned>(instr.sub_op.Value()));
+                UNIMPLEMENTED_MSG("Unhandled MUFU sub op={0:x}", instr.sub_op.Value());
                 return Immediate(0);
             }
         }();