cppcheck: Update the build target configuration

This patchs aligns the build command for cppcheck with
latest cmake targets. an521 has been renamed to mps/an521

Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
Change-Id: I4cab9f6341a5baec5eacd8364ef4ad11d660fcac
1 file changed