eal: calibrate TSC only in primary process

eal: calibrate TSC only in primary process

This ensures secondary processes never have to calculate the TSC rate
themselves, which can be noticeable in VMs that don't have access to
arch-specific detection mechanism (such as CPUID leaf 0x15 or MSR 0xCE
on x86).

Since rte_mem_config is now internal to the EAL library, we can add
tsc_hz without ABI breakage concerns.

Reduces rte_eal_init() execution time in a secondary process from 165ms
to 66ms on my test system.

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>