samples: usb: mass: Add support to TFM NS boards

This add TFM cmake definitions to build mass storage sample for non
secure firmware boards versions. The stm32l562e_dk_ns board was used
to demonstrate. It uses SDMMC/SD with TFM profile large. Tests were
conducted using a 2GB transflash card with FAT-32 partition.

Signed-off-by: Gerson Fernando Budke <gerson.budke@ossystems.com.br>