cpufreq: acpi-cpufreq: use DMI max speed when CPPC is unavailable

On AMD Ryzen Embedded V1780B (Family 17h, Zen 1), the BIOS does not
provide ACPI _CPC objects and the CPU does not support MSR-based CPPC
(X86_FEATURE_CPPC).  The _PSS table only lists nominal P-states
(P0 = 3350 MHz), so when get_max_boost_ratio() fails at
cppc_get_perf_caps(), cpuinfo_max_freq reports only the base frequency
instead of the rated boost frequency (3600 MHz).

  dmesg:
    ACPI CPPC: No CPC descriptor for CPU:0
    acpi_cpufreq: CPU0: Unable to get performance capabilities (-19)

cppc-cpufreq already has a DMI fallback (cppc_get_dmi_max_khz()) that
reads the processor max speed from SMBIOS Type 4.  Export it and reuse
it in acpi-cpufreq as a last-resort source for the boost frequency.

A sanity check ensures the DMI value is above the _PSS P0 frequency
and within 2x of it; values outside that range are ignored and the
existing arch_set_max_freq_ratio() path is taken instead.  The 2x
upper bound is based on a survey of the AMD Ryzen Embedded V1000
series, where the highest boost-to-base ratio is 1.8x (V1404I:
2.0 GHz base / 3.6 GHz boost).

The DMI lookup and sanity check are wrapped in a helper,
acpi_cpufreq_resolve_max_freq(), which falls through to
arch_set_max_freq_ratio() if the DMI value is absent or
out of range.

Tested on AMD Ryzen Embedded V1780B with v7.0-rc4:

  Before: cpuinfo_max_freq = 3350000 (base only)
  After:  cpuinfo_max_freq = 3600000 (includes boost)

Link: https://www.amd.com/en/products/embedded/ryzen/ryzen-v1000-series.html#specifications
Signed-off-by: Henry Tseng <henrytseng@qnap.com>
Link: https://patch.msgid.link/20260324090948.1667340-1-henrytseng@qnap.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>