kernel: mach SoC recognition for RV1106/RV1103 on 6.18 (M1 Step 3)

2-line DT-compat add to rockchip_board_dt_compat[] (rv1103 + rv1106), per the
breadth survey. Did NOT recreate the dropped CPU_RV1106 symbol (mainline IDs the
SoC purely via DT compat at runtime). clk + pinctrl + mach = the 3 core compile
components; DT + defconfig + full build remain for M2 (console boot).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017wB8KB3MMQztRDXCMCkPrf

kernel/rv1106-enablement/mach/0001-rv1106-soc-recognition.patch

@@ -0,0 +1,11 @@
+--- a/arch/arm/mach-rockchip/rockchip.c	2026-08-23 06:27:10.000000000 -0600
++++ b/arch/arm/mach-rockchip/rockchip.c	2026-08-23 12:41:37.714174678 -0600
+@@ -58,6 +58,8 @@
+ 	"rockchip,rk3188",
+ 	"rockchip,rk3228",
+ 	"rockchip,rk3288",
++	"rockchip,rv1103",
++	"rockchip,rv1106",
+ 	"rockchip,rv1108",
+ 	NULL,
+ };