mkdep.bat: fix spelling mistake "dependecies" -> "dependencies"
There is a spelling mistake in a REM remark comment. Fix it.
@@ -29,7 +29,7 @@ REM // Script to produce C/C++ dependencies based using CL compiler
REM //
REM // Using: deps.bat arg1 arg2 arg3
REM //
-REM // arg1 - C/C++ file name to produce dependecies for
+REM // arg1 - C/C++ file name to produce dependencies for
REM // arg2 - object file corresponding to the C/C++ file name
REM // arg3 - include switches for the compiler
REM //
