Several places in code for Hyper-V reference the
per-CPU variable hyperv_pcpu_input_arg. Older code uses a multi-line
sequence to reference the variable, and usually includes a cast.
Newer code does a much simpler direct assignment. The latter is
preferable as the complexity of the older code is unnecessary.

Update older code to use the simpler direct assignment.
Signed-off-by: Nischala Yelchuri <niyelchu@linux.microsoft.com>
Link: https://lore.kernel.org/r/1687286438-9421-1-git-send-email-niyelchu@linux.microsoft.comSigned-off-by: Wei Liu <wei.liu@kernel.org>