ASoC: SOF: amd: Add branch prediction hint in ACP IRQ handler

The conditional involving sdev->first_boot in acp_sof_ipc_irq_thread()
will succeed only once, i.e. during the very first run of the
DSP firmware.

Use the unlikely() annotation to help improve branch prediction
accuracy.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Reviewed-by: Venkata Prasad Potturu <venkataprasad.potturu@amd.com>
Link: https://patch.msgid.link/20250207-sof-vangogh-fixes-v1-4-67824c1e4c9a@collabora.com


Signed-off-by: Mark Brown <broonie@kernel.org>