ShellPkg: Fix several GCC compiler warnings

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10890 6f19259b-4bc3-4df7-8a09-765794883524

ShellPkg/Library/UefiShellLevel2CommandsLib/Cp.c

@@ -111,6 +111,8 @@ CopySingleFile(
           *Resp = Response;
         case ShellPromptResponseYes:
           break;
+        default:
+          return SHELL_ABORTED;
       }
     }
   }

ShellPkg/Library/UefiShellLevel2CommandsLib/Map.c

@@ -790,9 +790,9 @@ IsNumberLetterOnly(
   )
 {
   while(String != NULL && *String != CHAR_NULL) {
-    if (! ( *String >= L'a' && *String <= L'z'
-         || *String >= L'A' && *String <= L'Z'
-         || *String >= L'0' && *String <= L'9')
+    if (! ((*String >= L'a' && *String <= L'z') ||
+           (*String >= L'A' && *String <= L'Z') ||
+           (*String >= L'0' && *String <= L'9'))
         ){
       return (FALSE);
     }