samples: pfsm: add CC_CAN_LINK dependency

samples: pfsm: add CC_CAN_LINK dependency

When no libc for the target architecture is available, cross-compiling
the same cannot work:

samples/pfsm/pfsm-wakeup.c:12:10: fatal error: fcntl.h: No such file or directory

Fixes: 9e66fb5244953 ("samples: Add userspace example for TI TPS6594 PFSM")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20230616145013.3889906-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>