iwm: update rate tables from OpenBSD

These are from an earlier version of the driver (22-Oct-2021) which
I started to sync against back in 2021.

These pull in the rest of the VHT and HT rates.

Since that driver has functioning 802.11n support, it makes a good
intermediary checkpoint.

Locally tested:

• 7260, STA mode, 11g and 11a modes

Differential Revision: https://reviews.freebsd.org/D48209
Obtained from: OpenBSD (at a6e25c727a2214219715b51ba6af2221d7e0d674, 22-Oct-2021)