target/cortex_m: return error if breakpoint address is out of range

target/cortex_m: return error if breakpoint address is out of range

If the "Flash Patch and Breakpoint" unit is rev.1 then it can only
accept breakpoint addresses below 0x1FFFFFFF.
Detailed info in "ARM v7-M Architecture Reference Manual", DDI0403E
at chapter "C1.11 Flash Patch and Breakpoint unit".

Print a message and return error if the address of hardware
breakpoint cannot be handled by the breakpoint unit.

Change-Id: I95c92b1f058f0dfc568bf03015f99e439b27c59b
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/4535
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-by: Christopher Head <chead@zaber.com>