staging: unisys: Fix CamelCase in Issue_VMCALL_CHANNEL_MISMATCH()

Fix CamelCase names:
Issue_VMCALL_CHANNEL_MISMATCH => issue_vmcall_channel_mismatch
ChannelName => chname
ItemName => item_name
SourceLineNumber => line_no

Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>