staging: unisys: visorbus: Change support functions to integer return vals

Per Documentation/CodingStyle, function names that convey an action or an
imperative command should return an integer value. This commit changes
several functions and a macro, internal to visorchannel.c, to follow this
paradigm. These changes will be necessary later on to change other
functions in this file, which are part of the visorbus API, to return
integer values in lieu of a boolean.

Signed-off-by: David Binder <david.binder@unisys.com>
Signed-off-by: David Kershner <david.kershner@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>