realtek: Cleanup tab vs spaces for indentation

realtek: Cleanup tab vs spaces for indentation

Sources files should used for the proper indentation:

* use tabs instead of 8 spaces
* spaces should never directly before a tab
* no whitespace characters at the end of a line

These rules were partially not followed in various source files.

Signed-off-by: Sven Eckelmann <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/20895
Signed-off-by: Hauke Mehrtens <[email protected]>