eal: fix check of all requested CPU features

eal: fix check of all requested CPU features

Only the last feature was checked since commit 99f2cdf9ca10
(eal: fix %rbx corruption and simplify the code)

The return code for rte_cpu_get_flag_enabled is only checked on the termination
of the for loop that it is called inside, but should be checked for every
iteration it makes through the for loop.  This is caused by some silly missing
brackets.  Simply add them in

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Pablo De Lara Guarch  <pablo.de.lara.guarch@intel.com>
Acked-by: Thomas Monjalon <thomas.monjalon@6wind.com>