MdeModulePkg/Library: Fix typos in comments and variables

- servity -> severity
- TURE -> TRUE
- contiue -> continue
- Pepresentation -> Representation
- suported -> supported
- opints -> points
- sucessfully -> successfully
- hexidecimal -> hexadecimal
- Pacakge -> Package
- Libary -> Library
- successull -> successfully
- reseting -> resetting
- Retrive -> Retrieve
- dirver -> driver
- availible -> available
- chracter -> character
- seperator -> separator

Cc: Feng Tian <feng.tian@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>

MdeModulePkg/Library/DxeDebugPrintErrorLevelLib/DxeDebugPrintErrorLevelLib.c

@@ -248,7 +248,7 @@ GetDebugPrintErrorLevel (
         }
       } else {
         //
-        // If variable services are not yet availible optionally get the global
+        // If variable services are not yet available optionally get the global
         // debug print error level mask from a HOB.
         //
         Hob = GetFirstGuidHob (&gEfiGenericVariableGuid);