Bluetooth: Controller: Fix connection update interval_us variables

Fix connection update microsecond interval variable data
type, to use 32-bit so that a value upto 2000 seconds, i.e.
4 seconds interval and 499 peripheral latency can be stored.

Regression in commit abfe5f17a9 ("Bluetooth: Controller:
1 ms connection").

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>
(cherry picked from commit 0a4480ce61)

subsys/bluetooth/controller/ll_sw/ull_conn.c

@@ -2220,8 +2220,8 @@ void ull_conn_update_parameters(struct ll_conn *conn, uint8_t is_cu_proc, uint8_
 	uint16_t conn_interval_unit_old;
 	uint16_t conn_interval_unit_new;
 	uint32_t ticks_win_offset = 0U;
-	uint16_t conn_interval_old_us;
-	uint16_t conn_interval_new_us;
+	uint32_t conn_interval_old_us;
+	uint32_t conn_interval_new_us;
 	uint32_t ticks_slot_overhead;
 	uint16_t conn_interval_old;
 	uint16_t conn_interval_new;