core/hmi: Fix use of uninitialised value (CID 147808)
core/hmi: Fix use of uninitialised value (CID 147808)

A rework of where some of the xscom regs are for POWER9 has resulted in
a scope issue where the same line attempts to simultaneously reference a
variable by the same name in global and function scope.

Change the value read by xscom_read to *_val

Fixes: CID 147808
Fixes: bda5e0ea Fix scom addresses for power9 nx checkstop hmi handling.
Signed-off-by: Cyril Bur <6ce38dade8c4b52fd55c193fae70fd1d1275c3c3@au1.ibm.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

qemu/skiboot,shenki/skiboot,open-power/skiboot,legoater/skiboot,open-power/skiboot,open-power/skiboot,open-power/skiboot,stewart-ibm/skiboot,qemu/skiboot,legoater/skiboot,shenki/skiboot,shenki/skiboot,stewart-ibm/skiboot,qemu/skiboot,qemu/skiboot,open-power/skiboot,shenki/skiboot,legoater/skiboot,legoater/skiboot,stewart-ibm/skiboot,legoater/skiboot,shenki/skiboot,qemu/skiboot