bootstd: Add test for Android boot image v2

Rename actual android bootmethod test to specify it's for boot image
version 4.
Add a unit test for testing the Android bootmethod with boot image
version 2.

This requires another mmc image (mmc8) to contain the following
partitions:
- misc: contains the Bootloader Control Block (BCB)
- boot_a: contains a fake generic kernel image

we can test this with:

$ ./test/py/test.py --bd sandbox --build -k test_ut # build the mmc8.img
$ ./test/py/test.py --bd sandbox --build -k bootflow_android

Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Link: https://lore.kernel.org/r/20241126-adnroidv2-v4-5-11636106dc69@baylibre.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index dee2801..36cfbf2 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -44,6 +44,7 @@
 		mmc5 = "/mmc5";
 		mmc6 = "/mmc6";
 		mmc7 = "/mmc7";
+		mmc8 = "/mmc8";
 		pci0 = &pci0;
 		pci1 = &pci1;
 		pci2 = &pci2;
@@ -1138,13 +1139,20 @@
 		filename = "mmc6.img";
 	};
 
-	/* This is used for Android tests */
+	/* This is used for Android boot image v4 tests */
 	mmc7 {
 		status = "disabled";
 		compatible = "sandbox,mmc";
 		filename = "mmc7.img";
 	};
 
+	/* This is used for Android boot image v2 tests. */
+	mmc8 {
+		status = "disabled";
+		compatible = "sandbox,mmc";
+		filename = "mmc8.img";
+	};
+
 	pch {
 		compatible = "sandbox,pch";
 	};