pmdomain: qcom: rpmhpd: Add MXC to SC8280XP

This was apparently accounted for in dt-bindings, but never made its
way into the driver.

Fix it for SC8280XP and its VDD_GFX-less cousin, SA8540P.

Fixes: f68f1cb ("soc: qcom: rpmhpd: add sc8280xp & sa8540p rpmh power-domains")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20251202-topic-8280_mxc-v2-2-46cdf47a829e@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: quic-kdybcio

drivers/pmdomain/qcom/rpmhpd.c

@@ -246,6 +246,8 @@ static struct rpmhpd *sa8540p_rpmhpds[] = {
 	[SC8280XP_MMCX_AO] = &mmcx_ao,
 	[SC8280XP_MX] = &mx,
 	[SC8280XP_MX_AO] = &mx_ao,
+	[SC8280XP_MXC] = &mxc,
+	[SC8280XP_MXC_AO] = &mxc_ao,
 	[SC8280XP_NSP] = &nsp,
 };
 
@@ -700,6 +702,8 @@ static struct rpmhpd *sc8280xp_rpmhpds[] = {
 	[SC8280XP_MMCX_AO] = &mmcx_ao,
 	[SC8280XP_MX] = &mx,
 	[SC8280XP_MX_AO] = &mx_ao,
+	[SC8280XP_MXC] = &mxc,
+	[SC8280XP_MXC_AO] = &mxc_ao,
 	[SC8280XP_NSP] = &nsp,
 	[SC8280XP_QPHY] = &qphy,
 };