Input: hyperv-keyboard: Use in-place iterator API in the channel callback

Input: hyperv-keyboard: Use in-place iterator API in the channel callback

BugLink: https://bugs.launchpad.net/bugs/1843463
[ Upstream commit d09bc83640d524b8467a660db7b1d15e6562a1de ]

Simplify the ring buffer handling with the in-place API.

Also avoid the dynamic allocation and the memory leak in the channel
callback function.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>