realtek: Fix block comment style

realtek: Fix block comment style

In net code, it is preferred to have block comments which

* either are one line: `/* ... */`
* multiple lines with:
  - starting with the first comment line directly: `/* ...`
  - each line is intended with the first asterisk: ` * ...`
  - the last line is just the end of the comment:  ` */`

Signed-off-by: Sven Eckelmann <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/20906
Signed-off-by: Hauke Mehrtens <[email protected]>