[opus] Fix ARM cpu selection if Intrinsics are enabled but not asm

[Timothy B. Terriberry]

Jonathan Lennox wrote:
> The attached patch should fix this, by checking for a CPU feature if the feature or any higher feature is enabled in the configuration.

Applied, with the corrections to the priority of EDSP and Media we 
discussed on IRC, and also line breaks.

https://git.xiph.org/?p=opus.git;a=commitdiff;h=1a94b2b8797a