c++: modules: Fix 32-bit overflow with 64-bit location_t [PR117970]

c++: modules: Fix 32-bit overflow with 64-bit location_t [PR117970]

With the move to 64-bit location_t in r15-6016, I missed a spot in module.cc
where a location_t was still being stored in a 32-bit int. Fixed.

The xtreme-header* tests in modules.exp were still passing fine on lots of
architectures that were tested (x86-64, i686, aarch64, sparc, riscv64), but
the PR shows that they were failing in some particular risc-v multilib
configurations. They pass now.

gcc/cp/ChangeLog:

	PR c++/117970
	* module.cc (module_state::read_ordinary_maps): Change argument to
	line_map_uint_t instead of unsigned int.