lib: sbi: Add console_puts() callback in the console device

We add console_puts() callback in the console device which allows
console drivers (such as semihosting) to implement a specialized
way to output character string.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>