staging: rtl8723au: hal: Remove unnecessary function and its call

The function odm_DynamicBBPowerSaving23a on being called, simply returns
back. The function hasn't been mentioned in the TODO and doesn't have FIXME
code around. Hence, odm_DynamicBBPowerSaving23a and its calls have been
removed.

This was done using Coccinelle.

@@
identifier f;
@@

void f(...) {

-return;

}

Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>