power: rk808: rename to rk8xx

Since this driver can be used for rk8xx series pmic,
let's rename rk808 to rk8xx, to make it clear.

Configs parts are done by sed -i "s/RK808/RK8XX/g" `grep RK808 -lr ./`

Signed-off-by: Jacob Chen <jacob-chen@iotwrt.com>
diff --git a/configs/chromebook_minnie_defconfig b/configs/chromebook_minnie_defconfig
index 22e56b6..ef333c0 100644
--- a/configs/chromebook_minnie_defconfig
+++ b/configs/chromebook_minnie_defconfig
@@ -55,9 +55,9 @@
 CONFIG_PINCTRL_ROCKCHIP_RK3288=y
 CONFIG_DM_PMIC=y
 # CONFIG_SPL_PMIC_CHILDREN is not set
-CONFIG_PMIC_RK808=y
+CONFIG_PMIC_RK8XX=y
 CONFIG_DM_REGULATOR_FIXED=y
-CONFIG_REGULATOR_RK808=y
+CONFIG_REGULATOR_RK8XX=y
 CONFIG_PWM_ROCKCHIP=y
 CONFIG_RAM=y
 CONFIG_SPL_RAM=y