test: dfu: add some more test cases

On Tegra, the DFU buffer size is 1M. Consequently, the 8M test always
fails. Add tests for the 1M size, and one byte less as a corner case,
so that some large tests are executed and expected to pass.

Signed-off-by: Stephen Warren <swarren@nvidia.com>

test/dfu/dfu_gadget_test_init.sh

@@ -9,7 +9,7 @@ COLOUR_DEFAULT="\33[0m"
 
 LOG_DIR="./log"
 
-TEST_FILES_SIZES="63 64 65 127 128 129 4095 4096 4097 959 960 961 8M"
+TEST_FILES_SIZES="63 64 65 127 128 129 4095 4096 4097 959 960 961 1048575 1048576 8M"
 
 printf "Init script for generating data necessary for DFU test script"