gdbserver: disable attn after breaking
gdbserver: disable attn after breaking

Rather than leave attn enabled, disable it when breaking to idle state
if it was enabled. This helps prevent attn from getting left on after
the debugger is detached or when no breakpoints are enabled.

Signed-off-by: Nicholas Piggin <24829078df5003d9dd1dd871ca2aeb0b1cf95ef4@gmail.com>
Reviewed-by: Joel Stanley <4816dabf8db1bc6cac35b3a24cab2ff844b5b0c7@jms.id.au>
Signed-off-by: Joel Stanley <4816dabf8db1bc6cac35b3a24cab2ff844b5b0c7@jms.id.au>

open-power/pdbg,open-power/pdbg,open-power/pdbg