uboot-rockchip: Fix product name for Radxa ROCK Pi 4

"ROCK" is the correct series name.

 https://radxa.com/products/rock4

Signed-off-by: FUKAUMI Naoki <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/17532
Signed-off-by: Robert Marko <[email protected]>

package/boot/uboot-rockchip/Makefile

@@ -138,7 +138,7 @@ endef
 
 define U-Boot/rock-pi-4-rk3399
   $(U-Boot/rk3399/Default)
-  NAME:=Rock Pi 4
+  NAME:=ROCK Pi 4
   BUILD_DEVICES:= \
     radxa_rock-pi-4a
 endef