mtd: spi: Add lightweight SPI flash stack for SPL

Add a tiny SPI flash stack that just supports reading data/images from
SPI flash. This is useful for boards that have SPL size constraints and
would need to use SPI flash framework just to read images/data from
flash. There is approximately 1.5 to 2KB savings with this.

Based on prior work of reducing spi flash id table by
Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

Signed-off-by: Vignesh R <vigneshr@ti.com>
Tested-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Tested-by: Stefan Roese <sr@denx.de>
Tested-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com> #zynq-microzed
diff --git a/drivers/mtd/spi/Makefile b/drivers/mtd/spi/Makefile
index 70058d3..f99f6cb 100644
--- a/drivers/mtd/spi/Makefile
+++ b/drivers/mtd/spi/Makefile
@@ -4,12 +4,20 @@
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 
 obj-$(CONFIG_DM_SPI_FLASH) += sf-uclass.o
+spi-nor-y := sf_probe.o spi-nor-ids.o
 
 ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_SPL_SPI_BOOT)	+= fsl_espi_spl.o
+ifeq ($(CONFIG_SPL_SPI_FLASH_TINY),y)
+spi-nor-y += spi-nor-tiny.o
+else
+spi-nor-y += spi-nor-core.o
+endif
+else
+spi-nor-y += spi-nor-core.o
 endif
 
-obj-$(CONFIG_SPI_FLASH) += sf_probe.o spi-nor-core.o
+obj-$(CONFIG_SPI_FLASH) += spi-nor.o
 obj-$(CONFIG_SPI_FLASH_DATAFLASH) += sf_dataflash.o sf.o
 obj-$(CONFIG_SPI_FLASH_MTD) += sf_mtd.o
 obj-$(CONFIG_SPI_FLASH_SANDBOX) += sandbox.o