executer/exsystem: Add units to time variable names

`HowLong` refers to different units in both functions, so make it more
clear, what unit they expect. That also makes one comment superfluous.

source/components/executer/exsystem.c

@@ -265,7 +265,7 @@ AcpiExSystemWaitMutex (
  *
  * FUNCTION:    AcpiExSystemDoStall
  *
- * PARAMETERS:  HowLong         - The amount of time to stall,
+ * PARAMETERS:  HowLongUs       - The amount of time to stall,
  *                                in microseconds
  *
  * RETURN:      Status
@@ -280,29 +280,29 @@ AcpiExSystemWaitMutex (
 
 ACPI_STATUS
 AcpiExSystemDoStall (
-    UINT32                  HowLong)
+    UINT32                  HowLongUs)
 {
     ACPI_STATUS             Status = AE_OK;
 
 
     ACPI_FUNCTION_ENTRY ();
 
 
-    if (HowLong > 255) /* 255 microseconds */
+    if (HowLongUs > 255)
     {
         /*
-         * Longer than 255 usec, this is an error
+         * Longer than 255 microseconds, this is an error
          *
          * (ACPI specifies 100 usec as max, but this gives some slack in
          * order to support existing BIOSs)
          */
         ACPI_ERROR ((AE_INFO,
-            "Time parameter is too large (%u)", HowLong));
+            "Time parameter is too large (%u)", HowLongUs));
         Status = AE_AML_OPERAND_VALUE;
     }
     else
     {
-        AcpiOsStall (HowLong);
+        AcpiOsStall (HowLongUs);
     }
 
     return (Status);
@@ -313,7 +313,7 @@ AcpiExSystemDoStall (
  *
  * FUNCTION:    AcpiExSystemDoSleep
  *
- * PARAMETERS:  HowLong         - The amount of time to sleep,
+ * PARAMETERS:  HowLongMs       - The amount of time to sleep,
  *                                in milliseconds
  *
  * RETURN:      None
@@ -324,7 +324,7 @@ AcpiExSystemDoStall (
 
 ACPI_STATUS
 AcpiExSystemDoSleep (
-    UINT64                  HowLong)
+    UINT64                  HowLongMs)
 {
     ACPI_FUNCTION_ENTRY ();
 
@@ -337,12 +337,12 @@ AcpiExSystemDoSleep (
      * For compatibility with other ACPI implementations and to prevent
      * accidental deep sleeps, limit the sleep time to something reasonable.
      */
-    if (HowLong > ACPI_MAX_SLEEP)
+    if (HowLongMs > ACPI_MAX_SLEEP)
     {
-        HowLong = ACPI_MAX_SLEEP;
+        HowLongMs = ACPI_MAX_SLEEP;
     }
 
-    AcpiOsSleep (HowLong);
+    AcpiOsSleep (HowLongMs);
 
     /* And now we must get the interpreter again */