bhnd(4): Fix mips/broadcom core matching and bus pass order.
Changes:
- Fixed incorrect MIPS74k vendor ID in the bhnd core descriptor tables
- Fixed MIPS core driver's matching against MIPS/MIPS33 cores.
- Improved MIPS3302 core description.
- Enabled BUS_PASS_BUS on the bhnd nexus drivers to allow early probing of the MIPS core.
- Enabled BUS_PASS_CPU on the MIPS core driver to ensure correct attach order.
- Disabled matching of the MIPS core driver on non-SoC devices.
Reviewed by: Michael Zhilin <mizhka@gmail.com>
Approved by: adrian (mentor)
Differential Revision: https://reviews.freebsd.org/D6735