Improved biosdevname handling in first stage. bnc#821427

Original patch for bnc#821427 was submitted by Martin Wilck
(martin.wilck@ts.fujitsu.com).

It address feature implemented according fate#311332.
Changes:
- policy "all_names" was replaced by "physical". "all_names" was
removed even before biosdevname 0.3.8 (used in SLE-11-SP2).
"physical" is current default and recomended value for hotpluggable
systems

- smbios >= v2.6 is required as it introduces Type 41 record which
is needed by biosdevname

- nopirq disables usage of PCI Interrupt routing table as a
fallback in case of smbios failure. Suggested by DELL in the fate
Updated changelog.