Remove unneeded null check for entry in for loop
Remove unneeded null check for entry in for loop

In vpx_codec_control_(), before we enter the for loop, we have already
checked if ctx->iface->ctrl_maps is null and handle that as an error. So
the for loop can assume ctx->iface->ctrl_maps is not null, which implies
'entry' is not null (both initially and after entry++).

Change-Id: Ieafe464d4111fdb77f0586ecfa1835d1cfd44d94

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