target: Change policy of removing watchpoints/breakpoints.

Now internal watch/breakpoint will not be removed in case
of error during removing triggers from hardware.

Also change signature of some functions (for deletion
bp/wp) to print message in case of some error.

Change-Id: I71cd1f556a33975005d0ee372fc384fddfddc3bf
Signed-off-by: Kirill Radkin <kirill.radkin@syntacore.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7738


Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins