mesa/main: rename format-check function

mesa/main: rename format-check function

_mesa_es3_error_check_format_and_type isn't specific to OpenGL ES 3.x,
it applies to all versions of OpenGL ES. So let's rename it to reflect
this.

While we're at it, let's also rename a helper function it uses similarly.
As the helper is static, we can also remove the namespacing-prefix from
the name.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>