OpenBLAS

cpuid_zarch/hwcaps: add documentation and dump hwcaps in init

Add pointers to the definition of the hardware capability flags in glibc
and describe how they relate to the levels CPU_Z13 and CPU_Z14 for
optimized kernels.

To aid identifying available hardware capabilities and in debugging
potential build issues, dump their value in dynamic_arch_init() when
OPENBLAS_VERBOSE is set to 2 or higher.

Signed-off-by: Marius Hillenbrand <mhillen@linux.ibm.com>