GS290: Update mkbootimg.mk for Android 12

Fixes:
2022-02-13 17:14:20 - common.py - WARNING : Failure running ['imgdiff']:
imgdiff E 02-13 17:14:19 403626 403626 imgdiff.cpp:1407] Source and target don't have same number of chunks!

Traceback (most recent call last):
  File "/mnt/android/los19/out/host/linux-x86/bin/make_recovery_patch/internal/stdlib/runpy.py", line 174, in _run_module_as_main
  File "/mnt/android/los19/out/host/linux-x86/bin/make_recovery_patch/internal/stdlib/runpy.py", line 72, in _run_code
  File "/mnt/android/los19/out/host/linux-x86/bin/make_recovery_patch/__main__.py", line 12, in <module>
  File "/mnt/android/los19/out/host/linux-x86/bin/make_recovery_patch/internal/stdlib/runpy.py", line 174, in _run_module_as_main
  File "/mnt/android/los19/out/host/linux-x86/bin/make_recovery_patch/internal/stdlib/runpy.py", line 72, in _run_code
  File "/mnt/android/los19/out/host/linux-x86/bin/make_recovery_patch/make_recovery_patch.py", line 73, in <module>
  File "/mnt/android/los19/out/host/linux-x86/bin/make_recovery_patch/make_recovery_patch.py", line 69, in main
  File "/mnt/android/los19/out/host/linux-x86/bin/make_recovery_patch/common.py", line 3542, in MakeRecoveryPatch
  File "/mnt/android/los19/out/host/linux-x86/bin/make_recovery_patch/make_recovery_patch.py", line 67, in output_sink
TypeError: argument 1 must be string or buffer, not None

Change-Id: I7865a34d68659ef9bff44ae201e3c1e73012f019