irqchip/riscv-rpmi-sysmsi: Fix mailbox channel leak in rpmi_sysmsi_probe()

irqchip/riscv-rpmi-sysmsi: Fix mailbox channel leak in rpmi_sysmsi_probe()

commit 76f0930d6e809234904cf9f0f5f42ee6c1dc694e upstream.

When riscv_acpi_get_gsi_info() fails, the mailbox channel previously
requested via mbox_request_channel() is not freed. Add the missing
mbox_free_channel() call to prevent the resource leak.

Fixes: 4752b0cfbc37 ("irqchip/riscv-rpmi-sysmsi: Add ACPI support")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Reviewed-by: Rahul Pathak <rahul@summations.net>
Link: https://patch.msgid.link/20260315-sysmsi-v1-1-5f090c86c2ca@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>