[SCSI] libfc: fix RPORT_TO_PRIV and PRIV_TO_RPORT() macros.

These macros introduce extra undesirable semicolons that keep
them from being used in expressions, and they don't protect
against being passed an expression.

Add parens and remove the semicolons.

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>