eal/linux: fix out of bound access in hugepage init

eal/linux: fix out of bound access in hugepage init

Using IBM advance toolchain on Ubuntu 14.04 (package 8.0-3), gcc is complaining
about out of bound accesses.

  CC eal_hugepage_info.o
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:
In function ‘eal_hugepage_info_init’:
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:350:35:
error: array subscript is above array bounds [-Werror=array-bounds]
      internal_config.hugepage_info[j].hugepage_sz)
                                   ^
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:350:35:
error: array subscript is above array bounds [-Werror=array-bounds]
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:349:37:
error: array subscript is above array bounds [-Werror=array-bounds]
    if (internal_config.hugepage_info[j-1].hugepage_sz <
                                     ^
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:350:35:
error: array subscript is above array bounds [-Werror=array-bounds]
      internal_config.hugepage_info[j].hugepage_sz)

Looking at the code, these warnings are invalid from my pov and they disappeared
when upgrading the toolchain to new version (8.0-4).

However, the code was buggy (sorting code is wrong), so fix this by using qsort
and adding a check on num_sizes to avoid potential out of bound accesses.

Signed-off-by: David Marchand <david.marchand@6wind.com>
Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>