Documentation/networking: update git urls to use https over http

This fixes the following errors when trying to clone the urls:

Cloning into 'net'...
fatal: repository 'http://git.kernel.org/cgit/linux/kernel/git/davem/net.git/' not found
Cloning into 'net-next'...
fatal: repository 'http://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/' not found
Cloning into 'linux'...
fatal: repository 'http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/' not found
Cloning into 'stable-queue'...
fatal: repository 'http://git.kernel.org/cgit/linux/kernel/git/stable/stable-queue.git/

' not found

Signed-off-by: Alexander Alemayhu <alexander@alemayhu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>