Check NAL size before looking inside

Add a check to ensure we have a non-zero size for a NAL while
parsing before we crack said NAL open to see what type it is.

Bug: 72117051
Test: compilation
Change-Id: Iaa3ebb2daae5d9225060a11e9adbb6757a168656
Merged-In: I607c67a320b33b991476db30d78223cf4386c0e8
(cherry picked from commit e0c020969d88891b0b71bb938778e9ca762e8035)
1 file changed