[PATCH 2/2] mempool: use rte constant macro instead of GCC builtin

[Morten Brørup]

> From: Tyler Retzlaff [mailto:roretzla at linux.microsoft.com]
> Sent: Wednesday, 20 March 2024 22.34
> 
> Use newly introduced __rte_constant(e) macro instead of directly using
> __builtin_constant_p() allowing mempool to be built by MSVC.
> 
> Signed-off-by: Tyler Retzlaff <roretzla at linux.microsoft.com>
> ---

Reviewed-by: Morten Brørup <mb at smartsharesystems.com>