iwlwifi: pnvm: Fix a memory leak in 'iwl_pnvm_get_from_fs()'

A firmware is requested but never released in this function. This leads to
a memory leak in the normal execution path.

Add the missing 'release_firmware()' call.
Also introduce a temp variable (new_len) in order to keep the value of
'pnvm->size' after the firmware has been released.

Fixes: cdda18fb ("iwlwifi: pnvm: move file loading code to a separate function")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Luca Coelho <luca@coelho.fi>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1b5d80f54c1dbf85710fd285243932943b498fe7.1630614969.git.christophe.jaillet@wanadoo.fr

drivers/net/wireless/intel/iwlwifi/fw/pnvm.c

@@ -231,6 +231,7 @@ static int iwl_pnvm_get_from_fs(struct iwl_trans *trans, u8 **data, size_t *len)
 {
 	const struct firmware *pnvm;
 	char pnvm_name[MAX_PNVM_NAME];
+	size_t new_len;
 	int ret;
 
 	iwl_pnvm_get_fs_name(trans, pnvm_name, sizeof(pnvm_name));
@@ -242,11 +243,14 @@ static int iwl_pnvm_get_from_fs(struct iwl_trans *trans, u8 **data, size_t *len)
 		return ret;
 	}
 
+	new_len = pnvm->size;
 	*data = kmemdup(pnvm->data, pnvm->size, GFP_KERNEL);
+	release_firmware(pnvm);
+
 	if (!*data)
 		return -ENOMEM;
 
-	*len = pnvm->size;
+	*len = new_len;
 
 	return 0;
 }