arm64: cpufeature: 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: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/5a1b329cda34aec67615c0d2fd326eb0d6634bf7.1667336095.git.christophe.jaillet@wanadoo.frSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/kernel/cpufeature.c

@@ -65,6 +65,7 @@
 #include <linux/bsearch.h>
 #include <linux/cpumask.h>
 #include <linux/crash_dump.h>
+#include <linux/kstrtox.h>
 #include <linux/sort.h>
 #include <linux/stop_machine.h>
 #include <linux/sysfs.h>
@@ -1795,7 +1796,7 @@ kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
 static int __init parse_kpti(char *str)
 {
 	bool enabled;
-	int ret = strtobool(str, &enabled);
+	int ret = kstrtobool(str, &enabled);
 
 	if (ret)
 		return ret;
@@ -2039,7 +2040,7 @@ static bool enable_pseudo_nmi;
 
 static int __init early_enable_pseudo_nmi(char *p)
 {
-	return strtobool(p, &enable_pseudo_nmi);
+	return kstrtobool(p, &enable_pseudo_nmi);
 }
 early_param("irqchip.gicv3_pseudo_nmi", early_enable_pseudo_nmi);