[PATCH] eal: add support for TRNG with Arm RNG feature

[Wathsala Wathawana Vithanage]

> 
> If you decide to rte_csrand() it should fallback to get_random or get_entropy.
> 
> Note: many people don't fully trust RDRAND or ARM CPU instructions.
> That is why the Linux entropy calls do not use only the HW instructions.

Thanks Stephen. I understand the concern, would it be acceptable for you if
rte_csrand() by default used Linux entropy calls and still had a runtime parameter
to enable HW based csrng for supported CPU in rte_csrand for those who need it?