tests: drivers: watchdog: Excluding frdm_mcxw71 from basic api

The wdt_basic_api test uses retained memory. Currently,
uses sram0 for the ram space. This mostly does not retain
memory. Since the test variables are unable to retain
their value this platform test fails and should be excluded
for now.

Signed-off-by: Emilio Benavente <emilio.benavente@nxp.com>