net: wwan: iosm: remove unused enum definition

ipc_time_unit enum is defined but not used.
Remove it to avoid unexpected usage.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/8295a6138f13c686590ee4021384ee992f717408.1683649868.git.m.chetan.kumar@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/wwan/iosm/iosm_ipc_imem.h

@@ -140,17 +140,6 @@ enum ipc_channel_state {
 	IMEM_CHANNEL_CLOSING,
 };
 
-/* Time Unit */
-enum ipc_time_unit {
-	IPC_SEC = 0,
-	IPC_MILLI_SEC = 1,
-	IPC_MICRO_SEC = 2,
-	IPC_NANO_SEC = 3,
-	IPC_PICO_SEC = 4,
-	IPC_FEMTO_SEC = 5,
-	IPC_ATTO_SEC = 6,
-};
-
 /**
  * enum ipc_ctype - Enum defining supported channel type needed for control
  *		    /IP traffic.