lib: sbi: Show devices provided by platform in boot prints

We extend the boot-time prints to show various devices provided
(or registered) by the platform support. This will help users
verify hardware devices available for OpenSBI firmwares.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>