cosmetic: rockchip: rk3036: pinctrl: fix config symbol naming

Rockchip socs are always named rkxxxx in all places, as also shown
by the naming of the rk3036 pinctrl file itself.
Therefore also name the config symbol according to this scheme.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index 2067f87..29e6d85 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -121,7 +121,7 @@
 CONFIG_PINCTRL=y
 CONFIG_PINCONF=y
 CONFIG_ROCKCHIP_RK3288_PINCTRL=y
-CONFIG_ROCKCHIP_3036_PINCTRL=y
+CONFIG_ROCKCHIP_RK3036_PINCTRL=y
 CONFIG_PINCTRL_SANDBOX=y
 CONFIG_DM_PMIC=y
 CONFIG_PMIC_ACT8846=y