x86/xen: 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>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/e91af3c8708af38b1c57e0a2d7eb9765dda0e963.1667336095.git.christophe.jaillet@wanadoo.frSigned-off-by: Juergen Gross <jgross@suse.com>

arch/x86/xen/enlighten_pv.c

@@ -23,6 +23,7 @@
 #include <linux/start_kernel.h>
 #include <linux/sched.h>
 #include <linux/kprobes.h>
+#include <linux/kstrtox.h>
 #include <linux/memblock.h>
 #include <linux/export.h>
 #include <linux/mm.h>
@@ -113,7 +114,7 @@ static __read_mostly bool xen_msr_safe = IS_ENABLED(CONFIG_XEN_PV_MSR_SAFE);
 static int __init parse_xen_msr_safe(char *str)
 {
 	if (str)
-		return strtobool(str, &xen_msr_safe);
+		return kstrtobool(str, &xen_msr_safe);
 	return -EINVAL;
 }
 early_param("xen_msr_safe", parse_xen_msr_safe);

arch/x86/xen/setup.c

@@ -7,6 +7,7 @@
 
 #include <linux/init.h>
 #include <linux/sched.h>
+#include <linux/kstrtox.h>
 #include <linux/mm.h>
 #include <linux/pm.h>
 #include <linux/memblock.h>
@@ -85,7 +86,7 @@ static void __init xen_parse_512gb(void)
 	arg = strstr(xen_start_info->cmd_line, "xen_512gb_limit=");
 	if (!arg)
 		val = true;
-	else if (strtobool(arg + strlen("xen_512gb_limit="), &val))
+	else if (kstrtobool(arg + strlen("xen_512gb_limit="), &val))
 		return;
 
 	xen_512gb_limit = val;