effects: fix a theoretical memory leak

`realloc` doesn't deallocate `param` if it fails. Since the loop ends in
a `free`, we just need to avoid overwriting `param` until after the
check.

Caught by the static analyzer:

frameworks/av/services/audioflinger/Effects.cpp:1868:9: warning:
Potential leak of memory pointed to by 'param'
[clang-analyzer-unix.Malloc]

Bug: None
Test: TreeHugger

Change-Id: I58fe4319927b3ea99989e1fb1dc2dabe89c72ef8
1 file changed