[source] ipq806x: fix crash on 4.9 if the rpm clock probe happens before cpuidle init

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/2029167b565071f6fb19ee3d928779308e1a7ca3

commit 2029167b565071f6fb19ee3d928779308e1a7ca3
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Mon Mar 13 13:25:00 2017 +0100

    ipq806x: fix crash on 4.9 if the rpm clock probe happens before cpuidle init
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 .../patches-4.9/0070-qcom-spm-fix-probe-order.patch      | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/target/linux/ipq806x/patches-4.9/0070-qcom-spm-fix-probe-order.patch b/target/linux/ipq806x/patches-4.9/0070-qcom-spm-fix-probe-order.patch
new file mode 100644
index 0000000..b7e375d
--- /dev/null
+++ b/target/linux/ipq806x/patches-4.9/0070-qcom-spm-fix-probe-order.patch
@@ -0,0 +1,16 @@
+Check for SCM availability before attempting to use SPM
+
+Signed-off-by: Felix Fietkau <nbd at nbd.name>
+
+--- a/drivers/soc/qcom/spm.c
++++ b/drivers/soc/qcom/spm.c
+@@ -219,6 +219,9 @@ static int __init qcom_cpuidle_init(stru
+ 	cpumask_t mask;
+ 	bool use_scm_power_down = false;
+ 
++	if (!qcom_scm_is_available())
++		return -EPROBE_DEFER;
++
+ 	for (i = 0; ; i++) {
+ 		state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
+ 		if (!state_node)