[binutils-gdb] Constify language_enum

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 2039bd9f0ce667f3f0ee99c18e25de1ea18a2288 ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: 2039bd9f0ce667f3f0ee99c18e25de1ea18a2288

Constify language_enum

Change language_enum to take a const argument.

ChangeLog
2017-09-11  Tom Tromey  <tom@tromey.com>

	* language.h (language_enum): Make argument const.
	* language.c (language_enum): Make argument const.