[][Change mt7981 PWM patch format]

[Description]
Change PWM patch format

[Release-log]
N/A

Change-Id: I0cd893cab3b050a4e53f5a30d50543a554b93eaf
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5384647
diff --git a/target/linux/mediatek/patches-5.4/0931-pwm-add-mt7981-support.patch b/target/linux/mediatek/patches-5.4/0931-pwm-add-mt7981-support.patch
index d8b8434..dcaebb1 100644
--- a/target/linux/mediatek/patches-5.4/0931-pwm-add-mt7981-support.patch
+++ b/target/linux/mediatek/patches-5.4/0931-pwm-add-mt7981-support.patch
@@ -1,7 +1,7 @@
-diff --git a/build_dir/target-aarch64_cortex-a53_musl/linux-mediatek_mt7981/linux-5.4.163/drivers/pwm/pwm-mediatek.c b/build_dir/target-aarch64_cortex-a53_musl/linux-mediatek_mt7981/linux-5.4.163/drivers/pwm/pwm-mediatek.c
+diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
 index 7c56ee2..3a5a456 100644
---- a/build_dir/target-aarch64_cortex-a53_musl/linux-mediatek_mt7981/linux-5.4.163/drivers/pwm/pwm-mediatek.c
-+++ b/build_dir/target-aarch64_cortex-a53_musl/linux-mediatek_mt7981/linux-5.4.163/drivers/pwm/pwm-mediatek.c
+--- a/drivers/pwm/pwm-mediatek.c
++++ b/drivers/pwm/pwm-mediatek.c
 @@ -20,7 +20,6 @@
  #include <linux/slab.h>
  #include <linux/types.h>