flash: at91sam4: add support for the SAMG53 family (this also covers the
SAMG51).  The SAMG5x parts have an EEFC (enhanced embedded flash controller)
which seems to be identical to the EFC that the sam4 driver supports.

Add a script for the Xplained Pro G53 board, this has the onboard CMSIS-DAP
debugger and a SAMG53N19.  Tested on this board and chip combination.

Change-Id: I12af50402cd2069b3c7380d92e6fe54816d6c045
Signed-off-by: Andrey Yurovsky <yurovsky@gmail.com>
Reviewed-on: http://openocd.zylin.com/1974
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

These kits feature a CMSIS-DAP compliant debugger and so have been added
as part of the pending support.

Currently the flash drivers for the L8 and D20 are wip.

One issue this implementation of CMSIS-DAP raised is that it supports
512byte HID reports, however using the current HIDAPI we have no cross platform
way of querying this info. Long term we plan to add this support to HIDAPI.

Change-Id: Ie8b7c871f58a099d963cd71a9f8a0105a38784e9
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/1625
Tested-by: jenkins

Atmel introduced 6 new Cortex-M4 processors on 2011-10-26
SAM4S16C - 1024KB flash LQFP100/BGA100
SAM4S16B - 1024KB flash LQFP64/QFN64
SAM4S16A - 1024KB flash LQFP48/QFN48
SAM4S8C - 512KB flash LQFP100/BGA100
SAM4S8B - 512KB flash LQFP64/QFN64
SAM4S8A - 512KB flash LQFP48/QFN48

The SAM4S processors still suffer from the "6 waitstates needed
to program device" errata.

Other relevant changes are:
1. Address of flash memory starts at 0x400000.
2. EWP (Erase page and write page) only works for the first two 8KB "sectors"
3. Because of the EWP not working for all the sectors, normal page writes have
to be used.  The default_flash_blank_check is used to check if lockregions
should be erased.
4. The EA (Erase All) command takes 7.3s to complete. (Previous timeout was
500 ms)
5. There are 128 lockable regions of 8KB each.

Implemented default blank checking, and page erase for load_image scenarios.
This is to compensate for the EWP flash commands only working on the
first 2 8KB sectors.

Change-Id: I7c5a52b177f7849a107611fd0f635fc416cfb724
Signed-off-by: Olivier Schonken <olivier.schonken@gmail.com>
Reviewed-on: http://openocd.zylin.com/528
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>