staging: rtl8192u: fix comments in r819xU_phy.c

This patch fixes the comments in r819xU_phy.c by:
- replacing "// ..." with "/* .... */"
- removing unnecessary comments, the dates and names of
  developers from comments
- fixing some inconsistent comments
- fixing some typos
- fixing alignment issues

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>