examples: Update startup file and linker script targets

Each platform in mcu-driver-reference-platforms-for-arm now provides
startup file and linker script as separate CMake targets. This allows
applications to use a platform's default startup file which contains
handlers that interact well with the platform drivers, while using
a custom linker script for its own needs (e.g. larger stack size). Bump
the version of mcu-driver-reference-platforms-for-arm to bring in this
change.

Update the CMake targets for startup file and linker scripts linked by
the connectivity examples which rely on the HAL-provided timer handlers.

Signed-off-by: Lingkai Dong <lingkai.dong@arm.com>