bcm53xx: 5.4: enable NAND

NAND driver was dropped in the 5.4 bump, so enable it back

Fixes: 50c6938 ("bcm53xx: add v5.4 support")
Signed-off-by: DENG Qingfang <dengqf6@mail2.sysu.edu.cn>

target/linux/bcm53xx/config-5.4

@@ -307,8 +307,11 @@ CONFIG_MODULES_USE_ELF_REL=y
 CONFIG_MTD_BCM47XXSFLASH=y
 CONFIG_MTD_BCM47XX_PARTS=y
 # CONFIG_MTD_HYPERBUS is not set
+CONFIG_MTD_NAND_BRCMNAND=y
+CONFIG_MTD_NAND_CORE=y
+CONFIG_MTD_NAND_ECC_SW_HAMMING=y
 CONFIG_MTD_PARSER_TRX=y
-# CONFIG_MTD_RAW_NAND is not set
+CONFIG_MTD_RAW_NAND=y
 CONFIG_MTD_SPI_NOR=y
 CONFIG_MTD_SPLIT_SEAMA_FW=y
 CONFIG_MTD_UBI=y