sparc: Fix regset register window handling.

We have to adjust 'reg_window' down by 16 becuase the 'pos' iterator
we'll use to index into the stack slots will be between 16 and 32.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc arch/sparc/kernel/ptrace_32.c
Simple merge

diff --cc arch/sparc/kernel/ptrace_64.c
Simple merge