meter: replace color definitions

meter: replace color definitions

This patch implements the changes proposed in the deprecation
note[1]. Replace multiple color definitions in various places such as
rte_meter.h, rte_tm.h and rte_mtr.h with single rte_color defined
in rte_meter.h.

This is simple search and replace exercise without any implementation
change.

[1] https://mails.dpdk.org/archives/dev/2019-January/123861.html

Signed-off-by: Jasvinder Singh <jasvinder.singh@intel.com>
Acked-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>