intel_idle: stop exposing platform acronyms in sysfs

Cosmetic only -- no functional change in this patch.

sysfs before:

state4/desc:MWAIT 0x20
state4/name:C6-HSW

sysfs after:

state4/desc:MWAIT 0x20
state4/name:C6

We remove the platform acronyms from the end of the state name
(-HSW in this case) for three reasonse.

 1. more consistency with acpi_idle, which prints C1, C2, C3 etc.

 2. users know what platform they are on already
    an acronym for the processor code name here
    seems to cause more confusion than clarity.

 3. less clutter in "cpupower monitor" output,
    which truncates the names to 4 columns.

The precise definition of the state continues to be available in "desc".
Reported-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>