lib: utils/gpio: Generate FDT gpio driver list at compile-time

Instead of having FDT gpio driver list hard-coded in the C source,
we generate it using carray.sh at compile-time.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>