staging: r8188eu: convert pr_info_once call in core/rtw_fw.c

staging: r8188eu: convert pr_info_once call in core/rtw_fw.c

Convert pr_info_once call in core/rtw_fw.c to a dev_info_once call, as
ultimately, this results in the printing of the driver name anyway
(r8188eu) which is equally clear and removes the need for the "R8188EU: "
part of the format string.

Suggested-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20220520220953.11840-1-phil@philpotter.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>