mem: spi-mem: add declaration for spi_mem_default_supports_op

spi_mem_default_supports_op is used internally by controller
drivers to verify operation semantics are correct.

It is used internally inside spi-mem but has not (in U-Boot)
been declared in spi-mem.h for external use.

Signed-off-by: Mathew McBride <matt@traverse.com.au>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/include/spi-mem.h b/include/spi-mem.h
index ca0f55c..8be3e2b 100644
--- a/include/spi-mem.h
+++ b/include/spi-mem.h
@@ -240,6 +240,9 @@
 
 int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op);
 
+bool spi_mem_default_supports_op(struct spi_slave *mem,
+				 const struct spi_mem_op *op);
+
 #ifndef __UBOOT__
 int spi_mem_driver_register_with_owner(struct spi_mem_driver *drv,
 				       struct module *owner);