Embedded flash can have user signature area on SAMv7. This is a 512
bytes large page whose data are not erased by asserting ERASE pin or by
software ERASE command.
This commit adds arch to board interface for this area. It is possible
to perform read, write and erase operation. SAMV7_USER_SIGNATURE option
has to be set in the configuration.
Signed-off-by: Michal Lenc <michallenc@seznam.cz>
649ccb2d45