pinctrl: samsung: Fix NULL pointer exception on external interrupts on S3C24xx

pinctrl: samsung: Fix NULL pointer exception on external interrupts on S3C24xx

commit cee7413d84044a0c1919a7c70a2d761ae24390de upstream.

After commit 8b1bd11c1f8f ("pinctrl: samsung: Add the support the
multiple IORESOURCE_MEM for one pin-bank"), the S3C24xx (and probably
S3C64xx as well) fails:

	Unable to handle kernel NULL pointer dereference at virtual address 000000a8
	...
	(s3c24xx_demux_eint4_7) from [<c004469c>] (__handle_domain_irq+0x6c/0xcc)
	(__handle_domain_irq) from [<c0009444>] (s3c24xx_handle_irq+0x6c/0x12c)
	(s3c24xx_handle_irq) from [<c000e5fc>] (__irq_svc+0x5c/0x78)

Mentioned commit moved the pointer to controller's base IO memory address
from each controller's driver data (samsung_pinctrl_drv_data) to per-bank
structure (samsung_pin_bank).  The external interrupt demux
handlers (s3c24xx_demux_eint()) tried to get this base address from opaque
pointer stored under irq_chip data:

	struct irq_data *irqd = irq_desc_get_irq_data(desc);
	struct samsung_pin_bank *bank = irq_data_get_irq_chip_data(irqd);
	...
	pend = readl(bank->eint_base + EINTPEND_REG);

which is wrong because this is hardware irq and it bank was never set
for this irq_chip.

For S3C24xx and S3C64xx, this partially reverts mentioned commit by
bringing back the virt_base stored under each controller's driver data
(samsung_pinctrl_drv_data).  This virt_base address will be now
duplicated:
 - samsung_pinctrl_drv_data->virt_base: used on S3C24xx and S3C64xx,
 - samsung_pin_bank->pctl_base: used on Exynos.

Fixes: 8b1bd11c1f8f ("pinctrl: samsung: Add the support the multiple IORESOURCE_MEM for one pin-bank")
Cc: Sergio Prado <sergio.prado@e-labworks.com>
Reported-by: Sergio Prado <sergio.prado@e-labworks.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Lihua Yao <ylhuajnu@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>