[PATCH] irqdesc: Fix missing irq_to_desc export for !CONFIG_SPARSE_IRQ

In allmodconfig builds for sparc and any other arch which does not set CONFIG_SPARSE_IRQ, the following will be seen at modpost: CC [M] lib/cpu-notifier-error-inject.o CC [M] lib/pm-notifier-error-inject.o ERROR: "irq_to_desc" [drivers/gpio/gpio-mcp23s08.ko] undefined! make[2]: ***

[PATCH] irqdesc: Fix missing irq_to_desc export for !CONFIG_SPARSE_IRQ

In allmodconfig builds for sparc and any other arch which does not set CONFIG_SPARSE_IRQ, the following will be seen at modpost: CC [M] lib/cpu-notifier-error-inject.o CC [M] lib/pm-notifier-error-inject.o ERROR: irq_to_desc [drivers/gpio/gpio-mcp23s08.ko] undefined! make[2]: ***