cpufreq: tegra: don't error target() when suspended

cpufreq: tegra: don't error target() when suspended

bdd0d19b19e0 "cpufreq: move freq change notifications to cpufreq core"
added code to the cpufreq core to print an error if a cpufreq driver's
.target() function returned an error. This exposed the fact that Tegra's
cpufreq driver returns an error when it is ignoring requests due to the
system being suspended.

Modify Tegra's .target() function not to return an error in this case;
this prevents the error prints. The argument is that since the suspend
hook can't and doesn't inform the cpufreq core when its requests will
be ignored, there's no way for the cpufreq core to squelch them, so it's
not an error for the requests to keep coming. This change make the Tegra
driver consistent with how the Exynos handles the same situation. Note
that s5pv210-cpufreq.c probably suffers from this same issue though.

Fixes: bdd0d19b19e0 (cpufreq: move freq change notifications to cpufreq core)
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>