sparc, sparc64: fix redundant get_regs invocation

sparc, sparc64: fix redundant get_regs invocation

An explicit get_regs invocation was added to arch_set_error and
arch_set_success on sparc/sparc64 by commit v5.2~27 in attempt to fix
syscall tampering on these architectures when PTRACE_GET_SYSCALL_INFO
is in use.

That change, however, did not fix the bug because set_error and
set_success already invoke get_regs on all architectures where
ptrace_setregset_or_setregs is defined, this includes sparc and sparc64.

* linux/sparc/set_error.c (sparc_set_o0_psr): Do not invoke get_regs.
* linux/sparc64/set_error.c (sparc64_set_o0_tstate): Likewise.
* NEWS (5.2): Remove the statement about syscall tampering fix
on sparc and sparc64 when PTRACE_GET_SYSCALL_INFO is in use.