[bootstrap-O1] change value type to avoid sprintf buffer size warning

[bootstrap-O1] change value type to avoid sprintf buffer size warning

In stage2 of bootstrap-O1, the code that warns if sprintf might
overflow its output buffer cannot tell that an unsigned value narrowed
to 16 bits will fit in 4 bytes with %4x.

Converting the value to 'unsigned short' makes it obvious that it
fits, at least on machines with 16-bit shorts.

for  gcc/c-family/ChangeLog

	* c-pretty-print.c (pp_c_tree_decl_identifier): Convert 16-bit
	value to unsigned short to fit in 4 hex digits without
	warnings.

From-SVN: r244121