ARM: stm32: Rename update_sf to dh_update_sd_to_sf on STM32MP15xx DHCOR

Align the script name with DH i.MX8MP DHCOM script name. Add
backward compatibility script to avoid breaking user scripts.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/include/configs/stm32mp15_dh_dhsom.h b/include/configs/stm32mp15_dh_dhsom.h
index 9192169..c7ebf5c 100644
--- a/include/configs/stm32mp15_dh_dhsom.h
+++ b/include/configs/stm32mp15_dh_dhsom.h
@@ -20,7 +20,7 @@
 
 #define STM32MP_BOARD_EXTRA_ENV \
 	"usb_pgood_delay=1000\0" \
-	"update_sf=" /* Erase SPI NOR and install U-Boot from SD */	\
+	"dh_update_sd_to_sf=" /* Erase SPI NOR and install U-Boot from SD */ \
 		"setexpr loadaddr1 ${loadaddr} + 0x1000000 && "		\
 		"load mmc 0:4 ${loadaddr1} /boot/u-boot-spl.stm32 && "	\
 		"env set filesize1 ${filesize} && "			\
@@ -29,7 +29,9 @@
 		"sf update ${loadaddr1} 0 ${filesize1} && "		\
 		"sf update ${loadaddr1} 0x40000 ${filesize1} && "	\
 		"sf update ${loadaddr} 0x80000 ${filesize} && "		\
-		"env set filesize1 && env set loadaddr1\0"
+		"env set filesize1 && env set loadaddr1\0"		\
+	"update_sf=run dh_update_sd_to_sf\0"
+
 
 #include <configs/stm32mp15_common.h>