arm64: topology: Reorder init_amu_fie() a bit

arm64: topology: Reorder init_amu_fie() a bit

This patch does a couple of optimizations in init_amu_fie(), like early
exits from paths where we don't need to continue any further, avoid the
enable/disable dance, moving the calls to
topology_scale_freq_invariant() just when we need them, instead of at
the top of the routine, and avoiding calling it for the third time.

Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Ionela Voinescu <ionela.voinescu@arm.com>
Link: https://lore.kernel.org/r/a732e71ab9ec28c354eb28dd898c9b47d490863f.1610104461.git.viresh.kumar@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>