nand: atmel: Add DM based NAND driver

This implementation is ported from the rework done by Boris Brezillon
in Linux. This porting is done based on linux-5.4-at91. The driver is
tested in sam9x60ek, sama5d3_xplained, sam9x75eb and sama7g54-ddr3-eb.

Changes done includes

- Adapt GPIO descriptor apis for U-Boot. Use gpio_request_by_name_nodev,
  dm_gpio_get_value etc.
- Use U_BOOT_DRIVER instead of platform_driver.
- Replace struct platform_device with struct udevice
- Check the status of nfc exec operation by polling the status
  register instead of interrupt based handling
- DMA operations not supported. Remove it
- Adapt DT parsing to U-Boot APIs

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>

drivers/mtd/nand/raw/Kconfig

@@ -45,6 +45,14 @@ config SYS_NAND_NO_SUBPAGE_WRITE
 	bool "Disable subpage write support"
 	depends on NAND_ARASAN || NAND_DAVINCI || NAND_KIRKWOOD
 
+config DM_NAND_ATMEL
+       bool "Support Atmel NAND controller with DM support"
+       select SYS_NAND_SELF_INIT
+       imply SYS_NAND_USE_FLASH_BBT
+       help
+         Enable this driver for NAND flash platforms using an Atmel NAND
+         controller.
+
 config NAND_ATMEL
 	bool "Support Atmel NAND controller"
 	select SYS_NAND_SELF_INIT

drivers/mtd/nand/raw/Makefile

@@ -48,6 +48,7 @@ ifdef NORMAL_DRIVERS
 obj-$(CONFIG_NAND_ECC_BCH) += nand_bch.o
 
 obj-$(CONFIG_NAND_ATMEL) += atmel_nand.o
+obj-$(CONFIG_DM_NAND_ATMEL) += atmel/
 obj-$(CONFIG_NAND_ARASAN) += arasan_nfc.o
 obj-$(CONFIG_NAND_BRCMNAND) += brcmnand/
 obj-$(CONFIG_NAND_DAVINCI) += davinci_nand.o

drivers/mtd/nand/raw/atmel/Makefile

@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_DM_NAND_ATMEL)	+= atmel-nand-controller.o
+
+atmel-nand-controller-objs	:= nand-controller.o