imx8mm_beacon/imx8mn_beacon: Update build instructions

With binman generating flash.bin, it's not longer necessary to
specify either the location of ATF nor is it necessary to
specify building flash.bin, so let's update the build instructions
to remove those.  While in here, update the revision of ATF and
DDR firmware so both Mini and Nano reference the same revision.

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/board/beacon/imx8mm/README b/board/beacon/imx8mm/README
index 03d9412..c65acef 100644
--- a/board/beacon/imx8mm/README
+++ b/board/beacon/imx8mm/README
@@ -12,21 +12,21 @@
 Note: $(srctree) is U-Boot source directory
 
 $ git clone https://source.codeaurora.org/external/imx/imx-atf
-$ git checkout imx_5.4.70_2.3.0
+$ git lf-5.10.72-2.2.0
 $ make PLAT=imx8mm bl31 CROSS_COMPILE=aarch64-linux-gnu-
 $ cp build/imx8mm/release/bl31.bin $(srctree)
 
 Get the DDR firmware
 ====================
-$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.5.bin
-$ chmod +x firmware-imx-8.5.bin
-$ ./firmware-imx-8.5
-$ cp firmware-imx-8.5/firmware/ddr/synopsys/lpddr4*.bin $(srctree)
+$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.9.bin
+$ chmod +x firmware-imx-8.9.bin
+$ ./firmware-imx-8.9
+$ cp firmware-imx-8.9/firmware/ddr/synopsys/lpddr4*.bin $(srctree)
 
 Build U-Boot
 ============
 $ make imx8mm_beacon_defconfig
-$ make flash.bin CROSS_COMPILE=aarch64-linux-gnu-
+$ make CROSS_COMPILE=aarch64-linux-gnu-
 
 Burn U-Boot to microSD Card
 ===========================
diff --git a/board/beacon/imx8mn/README b/board/beacon/imx8mn/README
index a9eddd4..788ab10 100644
--- a/board/beacon/imx8mn/README
+++ b/board/beacon/imx8mn/README
@@ -12,9 +12,9 @@
 Note: $(srctree) is U-Boot source directory
 
 $ git clone https://source.codeaurora.org/external/imx/imx-atf
-$ git checkout imx_5.4.47_2.2.0
+$ git lf-5.10.72-2.2.0
 $ make PLAT=imx8mn bl31 CROSS_COMPILE=aarch64-linux-gnu-
-$ cp build/imx8mm/release/bl31.bin $(srctree)
+$ cp build/imx8mn/release/bl31.bin $(srctree)
 
 Get the DDR firmware
 ====================
@@ -26,7 +26,7 @@
 Build U-Boot
 ============
 $ make imx8mn_beacon_defconfig
-$ make flash.bin CROSS_COMPILE=aarch64-linux-gnu- ATF_LOAD_ADDR=0x960000
+$ make CROSS_COMPILE=aarch64-linux-gnu-
 
 Burn U-Boot to microSD Card
 ===========================