staging: unisys: remove channel mismatch macros

Simplify the code in channel.h by removing CHANNEL_GUID_MISMATCH,
CHANNEL_u64_MISMATCH, and CHANNEL_U32_MISMATCH, and printing the
messages directly instead.

The CamelCase names in the functions that used to use these macros will
be fixed in a later patch.

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