eal: fix build with icc

eal: fix build with icc

lib/librte_eal/linuxapp/eal/eal.c(461): error #2259: non-pointer
conversion from "long long" to "void *" may lose significant bits
   RTE_PTR_ALIGN_CEIL((uintptr_t)addr, RTE_PGSIZE_16M);

The root cause is that "RTE_PGSIZE_16M" is defined as unsigned long long.
But in i686 platform "void *" is 32-bit.
It is safe to cast to size_t and make it works in both 32 & 64-bit
platform.

Signed-off-by: Michael Qiu <michael.qiu@intel.com>
Acked-by: Thomas Monjalon <thomas.monjalon@6wind.com>