rapidio: improve a size determination in five functions

rapidio: improve a size determination in five functions

Replace the specification of data structures by pointer dereferences as
the parameter for the operator "sizeof" to make the corresponding size
determination a bit safer according to the Linux coding style
convention.

This issue was detected by using the Coccinelle software.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Markus Elfring <[email protected]>
Acked-by: Alexandre Bounine <[email protected]>
Cc: Matt Porter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>