drivers: hv: Fix hyperv_record_panic_msg path on comment

Fix the kernel parameter path in the comment, in the documentation the
parameter is correct but if someone who is studying the code and see
this first can get confused and try to access the wrong path/parameter

Signed-off-by: Matheus Castello <matheus@castello.eng.br>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20201115195734.8338-2-matheus@castello.eng.br
Signed-off-by: Wei Liu <wei.liu@kernel.org>

drivers/hv/vmbus_drv.c

@@ -55,7 +55,7 @@ int vmbus_interrupt;
 /*
  * Boolean to control whether to report panic messages over Hyper-V.
  *
- * It can be set via /proc/sys/kernel/hyperv/record_panic_msg
+ * It can be set via /proc/sys/kernel/hyperv_record_panic_msg
  */
 static int sysctl_record_panic_msg = 1;