Convert CONFIG_CMD_MAX6957 to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_MAX6957

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

board/work-microwave/work_92105/Kconfig

@@ -17,4 +17,11 @@ config CMD_HD44760
 	help
 	  This controls the LCD driver.
 
+config CMD_MAX6957
+	bool "Enable 'max6957aax' PMIC command"
+	help
+	  DEPRECATED: Needs conversion to driver model.
+
+	  This allows PMIC registers to be read and written.
+
 endif

configs/work_92105_defconfig

@@ -6,6 +6,7 @@ CONFIG_SPL_SERIAL_SUPPORT=y
 CONFIG_SPL_NAND_SUPPORT=y
 CONFIG_CMD_HD44760=y
 CONFIG_ENV_IS_IN_NAND=y
+CONFIG_CMD_MAX6957=y
 CONFIG_BOOTDELAY=3
 CONFIG_VERSION_VARIABLE=y
 # CONFIG_DISPLAY_BOARDINFO is not set

include/configs/work_92105.h

@@ -130,7 +130,6 @@
 
 #define CONFIG_LPC32XX_SSP
 #define CONFIG_LPC32XX_SSP_TIMEOUT 100000
-#define CONFIG_CMD_MAX6957
 /*
  * Environment
  */

scripts/config_whitelist.txt

@@ -293,7 +293,6 @@ CONFIG_CM922T_XA10
 CONFIG_CMDLINE_EDITING
 CONFIG_CMDLINE_PS_SUPPORT
 CONFIG_CMDLINE_TAG
-CONFIG_CMD_MAX6957
 CONFIG_CMD_MEM
 CONFIG_CMD_MFSL
 CONFIG_CMD_MMC_SPI