staging: r8188eu: use Linux kernel variable naming convention

staging: r8188eu: use Linux kernel variable naming convention

Follow the Linux Kernel coding style variable naming convention instead
of using camelCase style. Issue reported by checkpatch script for
these variables:
        tagLen, tagType, networkAddr, ipAddr, macAddr

Signed-off-by: Deepak R Varma <drv@mailo.com>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/a107c527e9032c22a62e93ff12d5fae625e70212.1666299151.git.drv@mailo.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>