Build failures in {v3.18,v4.4,v4.9}-stable-queue

[Guenter Roeck <linux@xxxxxxxxxxxx>]

Building xtensa:defconfig ... failed
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Error log:

arch/xtensa/kernel/process.c: In function 'get_wchan':
arch/xtensa/kernel/process.c:314:24: error: implicit declaration of function 'SPILL_SLOT'; did you mean 'PCI_SLOT'?

Guenter