cl-som-imx7: Remove CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR=y

Since commit 1da1938d ("spl: Add default values for ARCH_MX7")
CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR is selected by default on
i.MX7 platforms, so remove it from the board defconfig.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>

configs/cl-som-imx7_defconfig

@@ -17,7 +17,6 @@ CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=arch/arm/mach-imx/spl_sd.cfg"
 CONFIG_SPI_BOOT=y
 CONFIG_BOOTDELAY=3
 CONFIG_SPL_BOARD_INIT=y
-CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR=y
 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR=0x80
 CONFIG_SPL_I2C_SUPPORT=y
 CONFIG_SPL_SPI_LOAD=y