irqchip/goldfish-pic: Select GENERIC_IRQ_CHIP to fix build

irq-goldfish-pic uses GENERIC_IRQ_CHIP interfaces so select that symbol
to fix build errors.

Fixes these build errors:

mips-linux-ld: drivers/irqchip/irq-goldfish-pic.o: in function `goldfish_pic_of_init':
irq-goldfish-pic.c:(.init.text+0xc0): undefined reference to `irq_alloc_generic_chip'
mips-linux-ld: irq-goldfish-pic.c:(.init.text+0xf4): undefined reference to `irq_gc_unmask_enable_reg'
mips-linux-ld: irq-goldfish-pic.c:(.init.text+0xf8): undefined reference to `irq_gc_unmask_enable_reg'
mips-linux-ld: irq-goldfish-pic.c:(.init.text+0x100): undefined reference to `irq_gc_mask_disable_reg'
mips-linux-ld: irq-goldfish-pic.c:(.init.text+0x104): undefined reference to `irq_gc_mask_disable_reg'
mips-linux-ld: irq-goldfish-pic.c:(.init.text+0x11c): undefined reference to `irq_setup_generic_chip'
mips-linux-ld: irq-goldfish-pic.c:(.init.text+0x168): undefined reference to `irq_remove_generic_chip'

Fixes: 4235ff5 ("irqchip/irq-goldfish-pic: Add Goldfish PIC driver")
Signed-off-by: Randy Dunlap <[email protected]>
Reported-by: kernel test robot <[email protected]>
Cc: Miodrag Dinic <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Bartosz Golaszewski <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Goran Ferenc <[email protected]>
Cc: Aleksandar Markovic <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: rddunlap

drivers/irqchip/Kconfig

@@ -409,6 +409,7 @@ config MESON_IRQ_GPIO
 config GOLDFISH_PIC
        bool "Goldfish programmable interrupt controller"
        depends on MIPS && (GOLDFISH || COMPILE_TEST)
+       select GENERIC_IRQ_CHIP
        select IRQ_DOMAIN
        help
          Say yes here to enable Goldfish interrupt controller driver used