fpga: m10bmc-sec: Fix possible memory leak of flash_buf

There is an error check following the allocation of flash_buf that returns
without freeing flash_buf. It makes more sense to do the error check
before the allocation and the reordering eliminates the memory leak.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 154afa5 ("fpga: m10bmc-sec: expose max10 flash update count")
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220916235205.106873-1-russell.h.weight@intel.com
Signed-off-by: Xu Yilun <yilun.xu@intel.com>

Author: Russ Weight

drivers/fpga/intel-m10-bmc-sec-update.c

@@ -148,10 +148,6 @@ static ssize_t flash_count_show(struct device *dev,
 	stride = regmap_get_reg_stride(sec->m10bmc->regmap);
 	num_bits = FLASH_COUNT_SIZE * 8;
 
-	flash_buf = kmalloc(FLASH_COUNT_SIZE, GFP_KERNEL);
-	if (!flash_buf)
-		return -ENOMEM;
-
 	if (FLASH_COUNT_SIZE % stride) {
 		dev_err(sec->dev,
 			"FLASH_COUNT_SIZE (0x%x) not aligned to stride (0x%x)\n",
@@ -160,6 +156,10 @@ static ssize_t flash_count_show(struct device *dev,
 		return -EINVAL;
 	}
 
+	flash_buf = kmalloc(FLASH_COUNT_SIZE, GFP_KERNEL);
+	if (!flash_buf)
+		return -ENOMEM;
+
 	ret = regmap_bulk_read(sec->m10bmc->regmap, STAGING_FLASH_COUNT,
 			       flash_buf, FLASH_COUNT_SIZE / stride);
 	if (ret) {