drm/bridge: samsung-dsim: samsung_dsim_host_attach: don't use the bridge pointer...

drm/bridge: samsung-dsim: samsung_dsim_host_attach: don't use the bridge pointer as an error indicator

In preparation to handle refcounting of the out_bridge, we need to ensure
the out_bridge pointer contains either a valid bridge pointer or NULL, not
an ERR_PTR. Otherwise calls such as drm_bridge_get/put() would try to
redeference an ERR_PTR.

Stop using IS_ERR(next_bridge) as an indication of an error, and instead
use the 'ret' integer.

No functional change.

Acked-by: Maxime Ripard <mripard@kernel.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://patch.msgid.link/20260109-drm-bridge-alloc-getput-drm_of_find_bridge-2-v2-11-8bad3ef90b9f@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>