When seeding the pseudo-random number generator, replace the 64-bit
RDSEED with two 32-bit RDSEED instructions to allow building and
running on 32-bit x86.
Fixes: faf8fd252785 ("eal: improve entropy for initial PRNG seed")
Reported-by: Ferruh Yigit <ferruh.yigit@intel.com>
Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>