x86/mtrr: Remove unnecessary strlen() in mtrr_write()

The local variable length already holds the string length after calling
strncpy_from_user(). Using another local variable linlen and calling
strlen() is therefore unnecessary and can be removed. Remove linlen
and strlen() and use length instead.

No change in functionality intended.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250225131621.329699-2-thorsten.blum@linux.dev

arch/x86/kernel/cpu/mtrr/if.c

@@ -99,7 +99,6 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
 	char *ptr;
 	char line[LINE_SIZE];
 	int length;
-	size_t linelen;
 
 	memset(line, 0, LINE_SIZE);
 
@@ -108,9 +107,8 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
 	if (length < 0)
 		return length;
 
-	linelen = strlen(line);
-	ptr = line + linelen - 1;
-	if (linelen && *ptr == '\n')
+	ptr = line + length - 1;
+	if (length && *ptr == '\n')
 		*ptr = '\0';
 
 	if (!strncmp(line, "disable=", 8)) {