Microcode update check: use pfid mask in Intel source

[speed47]

Right now, we only take into account the CPUID to look for the proper microcode, but this is not sufficient for Intel as several distinct CPUs have the same CPUID but a different microcode version, in which case their PlatformID is different, and the proper microcode version that must be applied to them can be checked against the pf_mask (mask of PlatformIDs supported by this microccode) as reported by iucode_tool:

example:
078/004: sig 0x000106ca, pf_mask 0x10, 2009-08-25, rev 0x0107, size 5120