rockchip: build kernel with -O3 optimization

armv8/config-6.1

@@ -120,6 +120,8 @@ CONFIG_BSD_PROCESS_ACCT_V3=y
 # CONFIG_CACHEFILES_ONDEMAND is not set
 CONFIG_CC_HAVE_STACKPROTECTOR_SYSREG=y
 CONFIG_CC_IMPLICIT_FALLTHROUGH="-Wimplicit-fallthrough=5"
+# CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE is not set
+CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3=y
 CONFIG_CHARGER_GPIO=y
 CONFIG_CHR_DEV_SG=y
 CONFIG_CLKSRC_MMIO=y

patches-6.1/999-linux-O3.patch

@@ -0,0 +1,41 @@
+diff --git a/Makefile b/Makefile
+index 56afd1509..10b3a59b4 100644
+--- a/Makefile
++++ b/Makefile
+@@ -823,6 +823,9 @@ KBUILD_CFLAGS	+= $(call cc-disable-warning, address-of-packed-member)
+ ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
+ KBUILD_CFLAGS += -O2
+ KBUILD_RUSTFLAGS += -Copt-level=2
++else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3
++KBUILD_CFLAGS += -O3
++KBUILD_RUSTFLAGS += -Copt-level=3
+ else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
+ KBUILD_CFLAGS += -Os
+ KBUILD_RUSTFLAGS += -Copt-level=s
+diff --git a/init/Kconfig b/init/Kconfig
+index 94125d3b6..8ecbc5e96 100644
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -1405,7 +1405,7 @@ config INITRAMFS_PRESERVE_MTIME
+ 
+ choice
+ 	prompt "Compiler optimization level"
+-	default CC_OPTIMIZE_FOR_PERFORMANCE
++	default CC_OPTIMIZE_FOR_PERFORMANCE_O3
+ 
+ config CC_OPTIMIZE_FOR_PERFORMANCE
+ 	bool "Optimize for performance (-O2)"
+@@ -1414,6 +1414,13 @@ config CC_OPTIMIZE_FOR_PERFORMANCE
+ 	  with the "-O2" compiler flag for best performance and most
+ 	  helpful compile-time warnings.
+ 
++config CC_OPTIMIZE_FOR_PERFORMANCE_O3
++	bool "Optimize more for performance (-O3)"
++	imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED
++	help
++	  Choosing this option will pass "-O3" to your compiler to optimize
++	  the kernel yet more for performance.
++
+ config CC_OPTIMIZE_FOR_SIZE
+ 	bool "Optimize for size (-Os)"
+ 	help