Instead of having to enable ramfunc support manually, just make it
transparently available to users, keeping the MPU region disabled if not
used to not waste a MPU region. This however wastes 24 bytes of code
area when the MPU is disabled and 48 bytes when it is enabled, and
probably a dozen of CPU cycles during boot. I believe it is something
acceptable.
Note that when XIP is used, code is already in RAM, so the __ramfunc
keyword does nothing, but does not generate an error.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
992f29a1bc