ipmi: Fix __scan_channels() failing to rescan channels

ipmi: Fix __scan_channels() failing to rescan channels

[ Upstream commit 6bd30d8fc523fb880b4be548e8501bc0fe8f42d4 ]

channel_handler() sets intf->channels_ready to true but never
clears it, so __scan_channels() skips any rescan. When the BMC
firmware changes a rescan is required. Allow it by clearing
the flag before starting a new scan.

Signed-off-by: Jinhui Guo <guojinhui.liam@bytedance.com>
Message-ID: <20250930074239.2353-3-guojinhui.liam@bytedance.com>
Signed-off-by: Corey Minyard <corey@minyard.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>