bmips: add missing NAND config symbol

bcm6328, bcm6362 and bcm6368 targets are missing a key config symbol which
prevents the NAND from working.

Fixes: f6c02b014d9c ("bmips: 6.1: refresh config and add missing symbols")
Signed-off-by: Álvaro Fernández Rojas <[email protected]>
(cherry picked from commit 61da745817f28673b193d60bb4bc5b76dd215246)

target/linux/bmips/bcm6328/config-6.6

@@ -164,6 +164,7 @@ CONFIG_MTD_CFI_BE_BYTE_SWAP=y
 CONFIG_MTD_CFI_STAA=y
 CONFIG_MTD_JEDECPROBE=y
 CONFIG_MTD_NAND_BRCMNAND=y
+CONFIG_MTD_NAND_BRCMNAND_BCM63XX=y
 CONFIG_MTD_NAND_CORE=y
 CONFIG_MTD_NAND_ECC=y
 CONFIG_MTD_NAND_ECC_SW_HAMMING=y

target/linux/bmips/bcm6362/config-6.6

@@ -166,6 +166,7 @@ CONFIG_MTD_CFI_BE_BYTE_SWAP=y
 CONFIG_MTD_CFI_STAA=y
 CONFIG_MTD_JEDECPROBE=y
 CONFIG_MTD_NAND_BRCMNAND=y
+CONFIG_MTD_NAND_BRCMNAND_BCM63XX=y
 CONFIG_MTD_NAND_CORE=y
 CONFIG_MTD_NAND_ECC=y
 CONFIG_MTD_NAND_ECC_SW_HAMMING=y

target/linux/bmips/bcm6368/config-6.6

@@ -165,6 +165,7 @@ CONFIG_MTD_CFI_BE_BYTE_SWAP=y
 CONFIG_MTD_CFI_STAA=y
 CONFIG_MTD_JEDECPROBE=y
 CONFIG_MTD_NAND_BRCMNAND=y
+CONFIG_MTD_NAND_BRCMNAND_BCM63XX=y
 CONFIG_MTD_NAND_CORE=y
 CONFIG_MTD_NAND_ECC=y
 CONFIG_MTD_NAND_ECC_SW_HAMMING=y