test_firmware: Use kstrtobool() instead of strtobool()

strtobool() is the same as kstrtobool().
However, the latter is more used within the kernel.

In order to remove strtobool() and slightly simplify kstrtox.h, switch to
the other function name.

While at it, include the corresponding header file (<linux/kstrtox.h>)
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/34f04735d20e0138695dd4070651bd860a36b81c.1673688120.git.christophe.jaillet@wanadoo.frSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lib/test_firmware.c

@@ -22,6 +22,7 @@
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/delay.h>
+#include <linux/kstrtox.h>
 #include <linux/kthread.h>
 #include <linux/vmalloc.h>
 #include <linux/efi_embedded_fw.h>
@@ -358,7 +359,7 @@ static int test_dev_config_update_bool(const char *buf, size_t size,
 	int ret;
 
 	mutex_lock(&test_fw_mutex);
-	if (strtobool(buf, cfg) < 0)
+	if (kstrtobool(buf, cfg) < 0)
 		ret = -EINVAL;
 	else
 		ret = size;