net: miiphybb: Convert documentation to rst

Convert the current miiphybb documentation to rst. Rename
the README.bitbangMII to bitbangmii.rst in the process.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
3 files changed