irqchip/riscv-imsic: Fix output text of base address

The "per-CPU IDs ... at base ..." info log is outputting a physical
address, not a PPN.

Fixes: 027e125a ("irqchip/riscv-imsic: Add device MSI domain support for platform devices")
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/all/20240909085610.46625-2-ajones@ventanamicro.com