Decrease the number of SMB3 smbdirect client SGEs

The client-side SMBDirect layer requires no more than 6 send SGEs
and 1 receive SGE. The previous default of 8 send and 8 receive
causes smbdirect to fail on the SoftiWARP (siw) provider, and
possibly others. Additionally, large numbers of SGEs reduces
performance significantly on adapter implementations.

Also correct the frmr page count comment (not an SGE count).

Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Steve French <stfrench@microsoft.com>