Fix typo in ios RemotingPreferences.

Bug: None
Change-Id: I1cebed8f85622697230fe91dc165f3eb3d47e30e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2434144Reviewed-by: Yuwei Huang <yuweih@chromium.org>
Commit-Queue: Chunbo Hua <chunbo.hua@intel.com>
Cr-Commit-Position: refs/heads/master@{#812720}

remoting/ios/persistence/remoting_preferences.h

@@ -15,7 +15,7 @@ extern RemotingFlag const RemotingFlagLastSeenNotificationMessageId;
 extern RemotingFlag const RemotingFlagNotificationUiState;
 
 // |RemotingPreferences| is the centralized place to ask for information about
-// defaults and prefrences.
+// defaults and preferences.
 @interface RemotingPreferences : NSObject
 
 - (HostSettings*)settingsForHost:(NSString*)hostId;