[binutils-gdb] Change ch_type in Elf64_External_Chdr to 4 bytes

[sergiodj+buildbot at redhat dot com]

*** TEST RESULTS FOR COMMIT 7f7a1bce250bc286d23a4b895d684748bec03a71 ***

Author: H.J. Lu <hjl.tools@gmail.com>
Branch: master
Commit: 7f7a1bce250bc286d23a4b895d684748bec03a71

Change ch_type in Elf64_External_Chdr to 4 bytes

The ch_type field in Elf64_External_Chdr is 4 bytes, followed by a
4-byte padding.  This change doesn't introduce any functional change
since only the lower 32 bits of the ch_type field are used.

	* external.h (Elf64_External_Chdr): Change ch_type to 4 bytes
	and add ch_reserved.