brcm47xx: image: build alternative TRX using less optimized LZMA

There is a group of devices that lzma-loader doesn't work with. They
simply hang at "Starting program at 0x80001000" which is really hard to
debug and we didn't find any solution for this for years.

Broadcom doesn't use lzma-loader on these devices anyway. They decided
to drop lzma-loader and use less optimal LZMA compression that can be
handled by CFE itself (it doesn't use dictionary).

So support these devices we will need kernel compressed with different
parameters and trx without a loader.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

SVN-Revision: 42205