PM / devfreq: Fix typo in DFSO_DOWNDIFFERENTIAL macro name

Correct the spelling error in the DFSO_DOWNDIFFERENTIAL macro
definition and update the corresponding variable assignment.

The macro was previously misspelled as DFSO_DOWNDIFFERENCTIAL.
This change ensures consistent and correct spelling throughout
the simpleondemand governor implementation.

Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Link: https://patchwork.kernel.org/project/linux-pm/patch/20251118032339.2799230-1-luriwen@kylinos.cn/

Author: Riwen Lu

drivers/devfreq/governor_simpleondemand.c

@@ -14,15 +14,15 @@
 
 /* Default constants for DevFreq-Simple-Ondemand (DFSO) */
 #define DFSO_UPTHRESHOLD	(90)
-#define DFSO_DOWNDIFFERENCTIAL	(5)
+#define DFSO_DOWNDIFFERENTIAL	(5)
 static int devfreq_simple_ondemand_func(struct devfreq *df,
 					unsigned long *freq)
 {
 	int err;
 	struct devfreq_dev_status *stat;
 	unsigned long long a, b;
 	unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD;
-	unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL;
+	unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENTIAL;
 	struct devfreq_simple_ondemand_data *data = df->data;
 
 	err = devfreq_update_stats(df);