Fix offsets to access fpregset_t in sparc64-linux targets.

The %fsr register is not being properly accessed from gdb in
sparc64.  This is because sparc64_supply_fpregset and
sparc64_collect_fpregset are using the offsets from the
sparc32_bsd_fpregset constant instead of sparc64_bsd_fpregset.
This patch fixes this by registering the proper offsets for
sparc64-linux targets.

2014-02-14  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* sparc64-linux-nat.c (_initialize_sparc64_linux_nat): Register
	the proper offsets to access fpregset_t.