smb: fix SMB_READB, SMB_READW, SMB_PCALL to work as documented

smb: fix SMB_READB, SMB_READW, SMB_PCALL to work as documented

Previously, those ioctls were defined as 'in' only, so rdata.byte and
rdata.word were never updated in the userland.  The read data went only
to rbuf if it was provided.  Thus, consumers were forced to always use it.

Now the ioctls are marked as in-out.
Compatibility handlers are provided for old ioctls.

PR:		213481
Reported by:	Lewis Donzis <lew@perftech.com>
MFC after:	2 weeks
Relnotes:	maybe
Differential Revision: https://reviews.freebsd.org/D8430