configs: Move CONFIG_SPI_FLASH into defconfigs

Completely move CONFIG_SPI_FLASH from remaining board header files to
defconfigs

Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com> #zynq-microzed
diff --git a/configs/chromebit_mickey_defconfig b/configs/chromebit_mickey_defconfig
index fd4cd80..3ad4d7d 100644
--- a/configs/chromebit_mickey_defconfig
+++ b/configs/chromebit_mickey_defconfig
@@ -59,6 +59,7 @@
 CONFIG_PWRSEQ=y
 CONFIG_MMC_DW=y
 CONFIG_MMC_DW_ROCKCHIP=y
+CONFIG_SPI_FLASH=y
 CONFIG_PINCTRL=y
 CONFIG_SPL_PINCTRL=y
 CONFIG_DM_PMIC=y