cpufreq: cpufreq-dt: avoid uninitialized variable warnings:

gcc warns quite a bit about values returned from allocate_resources()
in cpufreq-dt.c:

cpufreq-dt.c: In function 'cpufreq_init':
cpufreq-dt.c:327:6: error: 'cpu_dev' may be used uninitialized in this function [-Werror=maybe-uninitialized]
cpufreq-dt.c:197:17: note: 'cpu_dev' was declared here
cpufreq-dt.c:376:2: error: 'cpu_clk' may be used uninitialized in this function [-Werror=maybe-uninitialized]
cpufreq-dt.c:199:14: note: 'cpu_clk' was declared here
cpufreq-dt.c: In function 'dt_cpufreq_probe':
cpufreq-dt.c:461:2: error: 'cpu_clk' may be used uninitialized in this function [-Werror=maybe-uninitialized]
cpufreq-dt.c:447:14: note: 'cpu_clk' was declared here

The problem is that it's slightly hard for gcc to follow return
codes across PTR_ERR() calls.

This patch uses explicit assignments to the "ret" variable to make
it easier for gcc to verify that the code is actually correct,
without the need to add a bogus initialization.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>