hwc_session: move a break

As written, this loop only runs once, which makes clang's new warning
unhappy:

hardware/qcom/sm8150/display/sdm/libs/hwc2/hwc_session.cpp:934:51:
error: loop will run at most once (loop increment never executed)
[-Werror,-Wunreachable-code-loop-increment]

Chatting with qcom, this appears to be a bug, and the best fix is to
move the `break` into the `if`.

Bug: 150166387
Test: TreeHugger
Change-Id: Icb64eed5b894b9188f5265094587dd802207ba66
1 file changed