Remove unnecessary null pointer checks

[elfring]

An extra null pointer check is not needed in functions like the following.

• co_delete
• DCifJSONStringHandler
• sunxi_init

[zoltanvb]

co_delete is a false match, I believe.
JSONStringHandler can be corrected eventually, it is indeed not useful
sunxi_init: even though technically it is not needed, I would leave it there in case there is some change to the code above.

[LibretroAdmin]

e30fcb6

I pushed through the change for JSONStringHandler.

[elfring]

Thanks for a source code improvement.

[elfring]

💭 I am curious if another software developer (besides me) can get into the mood to apply a corresponding update suggestion which could be generated by the software “Coccinelle” (also with the help of a variant from the following script).

@Remove_unnecessary_pointer_checks@
expression x;
@@
-if (\(x != 0 \| x != NULL\))
    free(x);