sf: Move SPI flash drivers to defconfig

There are already Kconfig options for SPI flash drivers, but we
have not moved them from config.h to defconfig files. This commit
does this in a batch.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/configs/sh7757lcr_defconfig b/configs/sh7757lcr_defconfig
index 1a253dc..54d6436 100644
--- a/configs/sh7757lcr_defconfig
+++ b/configs/sh7757lcr_defconfig
@@ -18,4 +18,5 @@
 # CONFIG_CMD_SETEXPR is not set
 # CONFIG_CMD_MISC is not set
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_USE_PRIVATE_LIBGCC=y