target/arm/hvf: switch hvf_arm_get_host_cpu_features to not create a vCPU

target/arm/hvf: switch hvf_arm_get_host_cpu_features to not create a vCPU

Creating a vCPU locks out APIs such as hv_gic_create().

As a result, switch to using the hv_vcpu_config_get_feature_reg interface.

Besides, all the following methods must be run on a vCPU thread:

  - hv_vcpu_create()
  - hv_vcpu_get_sys_reg()
  - hv_vcpu_destroy()

Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Mads Ynddal <mads@ynddal.dk>
Message-ID: <20250808070137.48716-3-mohamed@unpredictable.fr>
[PMD: Release config calling os_release()]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>