scsi: esas2r: unlock on error in esas2r_nvram_read_direct()

This error path is missing an unlock.

Fixes: 26780d9e ("[SCSI] esas2r: ATTO Technology ExpressSAS 6G SAS/SATA RAID Adapter Driver")
Link: https://lore.kernel.org/r/20191022102324.GA27540@mwandaSigned-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/esas2r/esas2r_flash.c

@@ -1197,6 +1197,7 @@ bool esas2r_nvram_read_direct(struct esas2r_adapter *a)
 	if (!esas2r_read_flash_block(a, a->nvram, FLS_OFFSET_NVR,
 				     sizeof(struct esas2r_sas_nvram))) {
 		esas2r_hdebug("NVRAM read failed, using defaults");
+		up(&a->nvram_semaphore);
 		return false;
 	}