apm821xx: replace DEVICE_{PROFILE|NAME} with BOARD_NAME

apm821xx: replace DEVICE_{PROFILE|NAME} with BOARD_NAME

This patch sets the BOARD_NAME variable on each affected
apm821xx device. The existing DEVICE_PROFILE and
DEVICE_NAME assignments are deprecated as they no longer
serve any purpose.

The BOARD_NAME variable is used by the sysupgrade-tar
method to specifiy a directory overwrite for the
sysupgrade-$dir directory in the generated tar file.
Keeping the original boardname in this context will be
necessary for targets that utilize the sysupgrade-tar
method. Otherwise, sysupgrade on an previous installation
will not recognize the newly generated images.

This step is necessary since an upcoming patch realigns
the existing shortname for a device with a proper
"manufacturer_device" identifier.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>