drm/nouveau/fb: restore init() for ramgp102

drm/nouveau/fb: restore init() for ramgp102

commit 6db9df4f7055eb4ea339e7b83ca676edd9ec1277 upstream.

init() was removed from ramgp102 when reworking the memory detection, as
it was thought that the code was only necessary when the driver performs
mclk changes, which nouveau doesn't support on pascal.

However, it turns out that we still need to execute this on some GPUs to
restore settings after DEVINIT, so revert to the original behaviour.

v2: fix tags in commit message, cc stable

Closes: https://gitlab.freedesktop.org/drm/nouveau/-/issues/319
Fixes: 2c0c15a22fa0 ("drm/nouveau/fb/gp102-ga100: switch to simpler vram size detection method")
Cc: stable@vger.kernel.org # 6.6+
Signed-off-by: Ben Skeggs <bskeggs@nvidia.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240904232418.8590-1-bskeggs@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>