Adjust ipmi device id to accept dbus versioning

Before this the ipmi device id would return
ipmitool -Idbus  mc info

...
Firmware Revision         : 0.06

Now it will track the version that you get from the version property of
/org/openbmc/inventory/system/chassis/motherboard/bmc
i.e.
version = v0.6-19-gf363f61-dirty
           ^ ^ ^^          ^
           | |  |----------|-- additional details
           | |---------------- Minor
           |------------------ Major

Now... ipmitool -Idbus  mc info
...
Firmware Revision         : 0.06
...
Aux Firmware Rev Info     :
    0x00
    0x19
    0x00
    0x01

If there is no -dirty (or anything really after the last '-') will force
the aux details byte 4 to 0.  A 0 means the FW image was created without
any changes in the yocto build.
1 file changed