cpufreq: amd-pstate: Fix the inconsistency in max frequency units

The nominal frequency in cpudata is maintained in MHz whereas all other
frequencies are in KHz. This means we have to convert nominal frequency
value to KHz before we do any interaction with other frequency values.

In amd_pstate_set_boost(), this conversion from MHz to KHz is missed,
fix that.

Tested on a AMD Zen4 EPYC server

Before:
$ cat /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq | uniq
2151
$ cat /sys/devices/system/cpu/cpufreq/policy*/cpuinfo_min_freq | uniq
400000
$ cat /sys/devices/system/cpu/cpufreq/policy*/scaling_cur_freq | uniq
2151
409422

After:
$ cat /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq | uniq
2151000
$ cat /sys/devices/system/cpu/cpufreq/policy*/cpuinfo_min_freq | uniq
400000
$ cat /sys/devices/system/cpu/cpufreq/policy*/scaling_cur_freq | uniq
2151000
1799527

Fixes: ec437d71

 ("cpufreq: amd-pstate: Introduce a new AMD P-State driver to support future processors")
Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@amd.com>
Acked-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Tested-by: Peter Jung <ptr1337@cachyos.org>
Cc: 5.17+ <stable@vger.kernel.org> # 5.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>