ntb_hw_switchtec: fix logic error

Newer gcc (version 7 and 8 presumably) warn about a statement mixing
the << operator with logical and:

drivers/ntb/hw/mscc/ntb_hw_switchtec.c: In function 'switchtec_ntb_init_sndev':
drivers/ntb/hw/mscc/ntb_hw_switchtec.c:888:24: error: '<<' in boolean context, did you mean '<' ? [-Werror=int-in-bool-context]

My interpretation here is that the author must have intended a bitmask
rather than a comparison, so I'm changing the '&&' to '&', which makes
a lot more sense in the context.

Fixes: 1b249475275d ("ntb_hw_switchtec: Allow using Switchtec NTB in multi-partition setups")
Reviewed-by: Logan Gunthorpe <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Jon Mason <[e-mail]>

drivers/ntb/hw/mscc/ntb_hw_switchtec.c

···
 		}
 
 		sndev->peer_partition = ffs(tpart_vec) - 1;
-		if (!(part_map && (1 << sndev->peer_partition))) {
+		if (!(part_map & (1 << sndev->peer_partition))) {
 			dev_err(&sndev->stdev->dev,
 				"ntb target partition is not NT partition\n");
 			return -ENODEV;