arm64: defconfig: Enable SPI NAND flashes

Add support for SPI NAND flashes on ARM64 boards/EVMs such as:

1. W35N01JW on AM62x LP SK, AM62A7 SK, J721S2 EVM, J784S4 EVM,
   J722S EVM, J742S2 EVM
2. W25N01JW on AM62Lx EVM

by enabling the MTD_SPI_NAND config as a module.

Signed-off-by: Santhosh Kumar K <s-k6@ti.com>
Link: https://lore.kernel.org/r/20250116035145.370734-1-s-k6@ti.com
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>

Author: Santhosh Kumar K

arch/arm64/configs/defconfig

@@ -285,6 +285,7 @@ CONFIG_MTD_NAND_BRCMNAND=m
 CONFIG_MTD_NAND_FSL_IFC=y
 CONFIG_MTD_NAND_QCOM=y
 CONFIG_MTD_SPI_NOR=y
+CONFIG_MTD_SPI_NAND=m
 CONFIG_MTD_UBI=m
 CONFIG_MTD_HYPERBUS=m
 CONFIG_HBMC_AM654=m