IOMX: do not clear buffer if it's allocated by component
Chong Zhang authored
The component might depends on their buffers to be initialized
in certain ways to work. Don't clear unless we're allocating it.

bug: 31586647
Change-Id: Ia0a125797e414998ef0cd8ce03672f5b1e0bbf7a
(cherry picked from commit ea76573a)
640b0412