SWDEV-450580 - Fix powercap set

Updates:
     * CLI - Added AMDSMIHelpers.convert_SI_unit() to help
       conversion of units
     * API - Reverted to uW for power cap limits
     * CLI - amd-smi static --limit now includes MIN_POWER
     * Tests now are all using uW units to keep W conversion
       to only happen in CLI
     * Python API now reflects same units as uW (what is seen
       in amdgpu driver)
     * CLI - amd-smi metric --power:
       Fixed power seen on gpu_metrics v1.3

Change-Id: I32d9ba78d0d8806772f0860f9a803a885b3f316a
Signed-off-by: Charis Poag <Charis.Poag@amd.com>

py-interface/README.md

@@ -414,13 +414,13 @@ Input parameters:
 
 Output: Dictionary with fields
 
-Field | Description
----|---
-`power_cap` |  power capability
-`dpm_cap` |  dynamic power management capability
-`default_power_cap` |  default power capability
-`min_power_cap` | min power capability
-`max_power_cap` | max power capability
+Field | Description | Units
+---|---|---
+`power_cap` |  power capability | uW
+`dpm_cap` |  dynamic power management capability | MHz
+`default_power_cap` |  default power capability | uW
+`min_power_cap` | min power capability | uW
+`max_power_cap` | max power capability | uW
 
 Exceptions that can be thrown by `amdsmi_get_power_cap_info` function: