efi_loader: efi_signal_event() fix comment typos

Add missing commas.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 3ab5eb5..a08630e 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -274,8 +274,8 @@
  * efi_signal_event() - signal an EFI event
  * @event:     event to signal
  *
- * This function signals an event. If the event belongs to an event group all
- * events of the group are signaled. If they are of type EVT_NOTIFY_SIGNAL
+ * This function signals an event. If the event belongs to an event group, all
+ * events of the group are signaled. If they are of type EVT_NOTIFY_SIGNAL,
  * their notification function is queued.
  *
  * For the SignalEvent service see efi_signal_event_ext.