EDAC/altera: Use fast register IO for S10 IRQs

When an IRQ occurs, regmap_{read,write,...}() is invoked in atomic
context. Regmap must indicate register IO is fast so that a spinlock is
used instead of a mutex to avoid sleeping in atomic context:

lock_acquire
__mutex_lock
mutex_lock_nested
regmap_lock_mutex
regmap_write
a10_eccmgr_irq_unmask
unmask_irq.part.0
irq_enable
__irq_startup
irq_startup
__setup_irq
request_threaded_irq
devm_request_threaded_irq
altr_sdram_probe

Mark it so.

[ bp: Massage. ]

Fixes: 3dab6bd52687 ("EDAC, altera: Add support for Stratix10 SDRAM EDAC")
Reported-by: Meng Li <[e-mail]>
Signed-off-by: Meng Li <[e-mail]>
Signed-off-by: Thor Thayer <[e-mail]>
Signed-off-by: Borislav Petkov <[e-mail]>
Cc: James Morse <[e-mail]>
Cc: linux-edac <[e-mail]>
Cc: Mauro Carvalho Chehab <[e-mail]>
Cc: Robert Richter <[e-mail]>
Cc: stable <[e-mail]>
Cc: Tony Luck <[e-mail]>
Link: https://lkml.kernel.org/r/[e-mail]

drivers/edac/altera_edac.c

···
 	.reg_write = s10_protected_reg_write,
 	.use_single_read = true,
 	.use_single_write = true,
+	.fast_io = true,
 };
 
 /************** </Stratix10 EDAC Memory Controller Functions> ***********/