mem: fix alignment parameter check

mem: fix alignment parameter check

In commit 2fc8d6d the behaviour of function rte_is_power_of_2 was
changed to not return true for 0. memzone_reserve_aligned_thread_unsafe
and rte_malloc_socket both make the assumption that for align = 0
!rte_is_power_of_2(align) will return false. This patch adds a check
that align parameter is non-zero before doing the power of 2 check.

Signed-off-by: Declan Doherty <declan.doherty@intel.com>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
[Thomas: use && operator instead of ternary ?: and fix precedence with parens]
Acked-by: Thomas Monjalon <thomas.monjalon@6wind.com>