misc: genwqe: Fix potential memory leak when pinning memory

Fix a memory leak in the genwqe_pin_mem() error path as called by
ioctl GENWQE_PIN_MEM. In case there is an error encountered when
mapping memory, the already allocated dma_mapping struct needs to
be freed correctly.

Detected by Coverity: CID 1162606.
Signed-off-by: Christian Engelmayer <cengelma@gmx.at>
Acked-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/genwqe/card_dev.c

@@ -787,6 +787,7 @@ static int genwqe_pin_mem(struct genwqe_file *cfile, struct genwqe_mem *m)
 	if (rc != 0) {
 		dev_err(&pci_dev->dev,
 			"[%s] genwqe_user_vmap rc=%d\n", __func__, rc);
+		kfree(dma_map);
 		return rc;
 	}