Rollup merge of #147268 - davidtwco:add-arm-maintainers-to-targets, r=lqd

add arm-maintainers to various targets

Add the ``@rust-lang/arm-maintainers`` team as maintainers to the following targets:

- `aarch64-unknown-linux-gnu`
- `aarch64-unknown-none`/`aarch64-unknown-none-softfloat`
- `aarch64-unknown-uefi`
- `armv7-unknown-linux-gnueabi`/`armv7-unknown-linux-gnueabihf`
- `armv7a-none-eabi`/`armv7a-none-eabihf`
- `armv7r-none-eabi`/`armv7r-none-abihf`
- `armv8r-none-eabihf`
- `thumbv7em-none-eabi`/`thumbv7em-none-eabihf`
- `thumbv7m-none-eabi`
- `thumbv8m.base-none-eabi`
- `thumbv8m.main-none-eabi`/`thumbv8m.main-none-eabihf`

cc `@thejpster`

Author: Zalathar