Kinetis flash driver services huge number of MCU types. They have
one, two or four flash banks with option of FlexNVM. It would
require ~36 config files just for Kx series, more for KLx, KVx and KE1x.

The change implements alternative approach:
- configuration file creates just one pflash bank (common for all devices)
- when a device is probed, additional pflash or flexnvm banks are created
based on flash layout of the connected MCU
- created banks have names with optional numbering e.g. kx.pflash0 kx.pflash1
kx.flexnvm0 kx.flexnvm1
- the first bank gets renamed if numbering is used

Automatic bank creation is enabled by tcl command 'kinetis create_banks'.

Used solution has a drawback: other banks than pflash0 are not accessible
until pflash0 is probed. Fortunately gdb attach and standard programming
accesses banks in right sequence.

Change-Id: I5b9037cbefdb8a4176b7715fbcc3af4da4c1ab60
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/3925


Tested-by: jenkins
Reviewed-by: Joakim Nohlgård <joakim.nohlgard@eistec.se>
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>