TableGen/GlobalISel: Fix using wrong type for instruction flags

09515f2c20111628ce81ad5f40e12e5f6af5ed2f increased the size of the
MachineInstr flags from uint16_t to uint32_t, so change TableGen
to match.
diff --git a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.h b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.h
index 3156064..43b0eb5 100644
--- a/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.h
+++ b/llvm/utils/TableGen/Common/GlobalISel/GlobalISelMatchTable.h
@@ -55,7 +55,7 @@
   GISF_IgnoreCopies = 0x1,
 };
 
-using GISelFlags = std::uint16_t;
+using GISelFlags = std::uint32_t;
 
 //===- Helper functions ---------------------------------------------------===//