95nvmf: add NVMe over TCP support

95nvmf: add NVMe over TCP support

Add support to boot from an NVMe over TCP device.

Example of supported command line formats:

nvme.discover=tcp:192.168.1.3::4420
nvme.discover=tcp:192.168.1.3 # will use 4420 as default svcid

- Create is_nvmf() function to handle all fabrics types
- Fix parse_nvmf_discover() to correctly use the default values
- Auxiliary function to validate an IP connection
- Fix inverted result for getargbool when reading "rd.nonvmf" command line parameter

Requires rd.neednet=1
Requires adding/replacing STARTMODE in /etc/sysconfig/network/ifcfg-ethX to "nfsroot"
to avoid shutdown hanging in initiator

Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>