mfd: sm501: Set coherent_dma_mask when creating subdevices

Instantiating the sm501 OHCI subdevice results in a kernel warning.

sm501-usb sm501-usb: SM501 OHCI
sm501-usb sm501-usb: new USB bus registered, assigned bus number 1
WARNING: CPU: 0 PID: 1 at ./include/linux/dma-mapping.h:516
ohci_init+0x194/0x2d8
Modules linked in:

CPU: 0 PID: 1 Comm: swapper Tainted: G W
4.18.0-rc7-00178-g0b5b1f9a78b5 #1
PC is at ohci_init+0x194/0x2d8
PR is at ohci_init+0x168/0x2d8
PC : 8c27844c SP : 8f81dd94 SR : 40008001
TEA : 29613060
R0 : 00000000 R1 : 00000000 R2 : 00000000 R3 : 00000202
R4 : 8fa98b88 R5 : 8c277e68 R6 : 00000000 R7 : 00000000
R8 : 8f965814 R9 : 8c388100 R10 : 8fa98800 R11 : 8fa98928
R12 : 8c48302c R13 : 8fa98920 R14 : 8c48302c
MACH: 00000096 MACL: 0000017c GBR : 00000000 PR : 8c278420

Call trace:
[<(ptrval)>] usb_add_hcd+0x1e8/0x6ec
[<(ptrval)>] _dev_info+0x0/0x54
[<(ptrval)>] arch_local_save_flags+0x0/0x8
[<(ptrval)>] arch_local_irq_restore+0x0/0x24
[<(ptrval)>] ohci_hcd_sm501_drv_probe+0x114/0x2d8
...

Initialize coherent_dma_mask when creating SM501 subdevices to fix
the problem.

Fixes: b6d6454fdb66f ("mfd: SM501 core driver")
Signed-off-by: Guenter Roeck <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/sm501.c

···
 	smdev->pdev.name = name;
 	smdev->pdev.id = sm->pdev_id;
 	smdev->pdev.dev.parent = sm->dev;
+	smdev->pdev.dev.coherent_dma_mask = 0xffffffff;
 
 	if (res_count) {
 		smdev->pdev.resource = (struct resource *)(smdev+1);