cpufreq: Remove duplicate check in __cpufreq_offline()

The has_target() checks in __cpufreq_offline() are duplicate.

Remove one of them and put the operations of exiting governor together
with storing last governor's name.

Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Link: https://patch.msgid.link/20250623133402.3120230-5-zhenglifeng1@huawei.com


Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>