* sparc-tdep.c (sparc_frame_cache): Adjust cached frame base

* sparc-tdep.c (sparc_frame_cache): Adjust cached frame base
address for 64-bit code.
(sparc_unwind_dummy_id): Likewise.
* sparc64-tdep.c (sparc64_frame_prev_register): Adjust for new
frame base address convention.
(sparc64_push_dummy_call): Likewise.
* sparc64nbsd-tdep.c: Update copyright year.
(sparc64nbsd_sigcontext_frame_cache): Adjust cached frame base
address for 64-bit code.
(sparc64nbsd_init_abi): Tweak comment.
* sparc64obsd-tdep.c: Update copyright year.
(sparc64obsd_frame_cache): Adjust cached frame base address for
64-bit code.
(sparc64obsd_init_abi): Tweak comment.