examples/l3fwd-power: exit on power lib init failure
examples/l3fwd-power: exit on power lib init failure

Currently, if power library initialization fails, only a log message is
displayed. This is suboptimal for a number of reasons, but the main one
is that telemetry mode does not depend on the power library and can
therefore run in environments where l3fwd-power would normally not run
correctly (such as inside a VM). This will lead to attempts to
deinitialize the power library on exit, with a subsequent forced unclean
shutdown of DPDK.

Fix this by only initializing the power library in modes that actually
need it, and change a log message to a failure to initialize.

Signed-off-by: Anatoly Burakov <814e00d8f6e4e81b7ccc7e3e5a0bfec0078f0203@intel.com>
Acked-by: David Hunt <763be7c8e0ad91e03160e7aed76d5cd41534e2f9@intel.com>
Reviewed-by: Reshma Pattan <4d9eb35579760ed1c2db754a6b402039c9c8a1cb@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk