soc: qcom: ramp_controller: Fix an error handling path in qcom_ramp_controller_probe()

'qrc' is known to be non-NULL at this point.
Checking for 'qrc->desc' was expected instead, so use it.

Fixes: a723c95f ("soc: qcom: Add Qualcomm Ramp Controller driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/84727a79d0261b4112411aec23b553504015c02c.1681684138.git.christophe.jaillet@wanadoo.fr