Pass aarch64_debug_reg_state to functions

Pass aarch64_debug_reg_state to functions

Some functions on handling HW watchpoint in GDB and GDBserver looks the
same except the code getting debug register state from current inferior.
In GDB, we get debug register state like this:

  state = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));

while in GDBserver, we get debug register state like this:

  state = aarch64_get_debug_reg_state ();

This patch is to move two lines above out of some functions, and pass
aarch64_debug_reg_state to these functions, in this way, these functions
are the same, and can be moved to a common place.

gdb:

2015-07-17  Yao Qi  <yao.qi@linaro.org>

	* aarch64-linux-nat.c (aarch64_handle_breakpoint): Add argument
	state and don't call aarch64_get_debug_reg_state.  All callers
	update.
	(aarch64_linux_insert_hw_breakpoint): Call
	aarch64_get_debug_reg_state earlier.
	(aarch64_linux_remove_hw_breakpoint): Likewise.
	(aarch64_handle_aligned_watchpoint): Add argument state and
	don't call aarch64_get_debug_reg_state.  All callers update.
	(aarch64_handle_unaligned_watchpoint): Likewise.
	(aarch64_handle_watchpoint): Add argument state.
	(aarch64_linux_insert_watchpoint): Call aarch64_get_debug_reg_state
	earlier.
	(aarch64_linux_remove_watchpoint): Likewise.

gdb/gdbserver:

2015-07-17  Yao Qi  <yao.qi@linaro.org>

	* linux-aarch64-low.c (aarch64_handle_breakpoint): Add argument state
	and don't aarch64_get_debug_reg_state.  All callers update.
	(aarch64_handle_aligned_watchpoint): Likewise.
	(aarch64_handle_unaligned_watchpoint): Likewise.
	(aarch64_handle_watchpoint): Likewise.
	(aarch64_insert_point): Call aarch64_get_debug_reg_state earlier.
	(aarch64_remove_point): Likewise.