gpu: nova-core: vbios: Add support to look up PMU table in FWSEC

The PMU table in the FWSEC image has to be located to locate the start
of the Falcon ucode in the same or another FWSEC image. Add support for
the same.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250619-nova-frts-v6-18-ecf41ef99252@nvidia.com


[ Re-format and use markdown in comments. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>