Update family and model detection for AMD CPUs

Update family and model detection for AMD CPUs

AMD CPUs uses the similar encoding scheme for extended family and model
as Intel CPUs as shown in:

http://support.amd.com/TechDocs/25481.pdf

This patch updates get_common_indeces to get family and model for both
Intel and AMD CPUs when family == 0x0f.

	[BZ #19214]
	* sysdeps/x86/cpu-features.c (get_common_indeces): Add an
	argument to return extended model.  Update family and model
	with extended family and model when family == 0x0f.
	(init_cpu_features): Updated.