[binutils-gdb] Remove regcache_get_ptid

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 222312d359fe0a68f8583ba315583ee8cc94f252 ***

Author: Simon Marchi <simon.marchi@ericsson.com>
Branch: master
Commit: 222312d359fe0a68f8583ba315583ee8cc94f252

Remove regcache_get_ptid

Remove regcache_get_ptid, change all callers to call the regcache method
directly.

gdb/ChangeLog:

	* regcache.h (regcache_get_ptid): Remove, update all callers to
	call regcache::ptid instead.
	* regcache.c (regcache_get_ptid): Remove.