Previously, in an effort to defer initializing the gpu until firmware
was available (ie. rootfs mounted), the gpu was not loaded at when the
subdevice was bound.  Which resulted that clks/etc were requested in a
place that devm couldn't really help unwind if something failed.

Instead move request_firmware() to gpu->hw_init() and construct the gpu
earlier in adreno_bind().  To avoid the rest of the driver needing to
be aware of a gpu that hasn't managed to load firmware and hw_init()
yet, stash the gpu ptr in the adreno device's drvdata, and don't set
priv->gpu() until hw_init() succeeds.
Signed-off-by: Rob Clark <robdclark@gmail.com>