net/ice/base: read PSM clock frequency from register

net/ice/base: read PSM clock frequency from register

Read the GLGEN_CLKSTAT_SRC register to determine which PSM clock
frequency is selected.  This ensures that the rate limiter profile
calculations will be correct.

Fixes: 453d087ccaff ("net/ice/base: add common functions")
Cc: stable@dpdk.org
Signed-off-by: Ben Shelton <benjamin.h.shelton@intel.com>
Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Qiming Yang <qiming.yang@intel.com>