panfrost/midgard: Emit extended branches

panfrost/midgard: Emit extended branches

Previously, we only emitted compact branches; however, the offset range
of these branches is too small for many real world shaders. This patch
implements support for emitting extended branches and switches to always
using them for control flow. This incurs a code size and possibly
performance penalty, but expands the range of working shaders and
provides opportunity for further optimization.

Support for emitting compact branches is retained but this code path is
presently unused. In the future, we'll want to heuristically determine
which type of branch should be emitted for optimal codegen.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>