staging: rtl8172: Add blank lines after declarations

Add blank lines as reported by checkpatch.pl as below

CHECK: Please use a blank line after function/struct/union/enum declarations

Signed-off-by: Srihari S <sriharisat@gmail.com>
Link: https://lore.kernel.org/r/1680966983-11609-1-git-send-email-sriharisat@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>