remoteproc/mtk_scpi_ipi: Fix one kernel-doc comment

Fix the function name in kernel-doc comments to clear the below
warning:

drivers/remoteproc/mtk_scp_ipi.c:136: warning: expecting prototype for scp_ipi_lock(). Prototype was for scp_ipi_unlock() instead

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4544
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230316084011.99613-1-yang.lee@linux.alibaba.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>