EDAC/altera: Use fast register IO for S10 IRQs

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 <Meng.Li@windriver.com>
Signed-off-by: Meng Li <Meng.Li@windriver.com>
Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: James Morse <james.morse@arm.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Robert Richter <rrichter@marvell.com>
Cc: stable <stable@vger.kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/1574361048-17572-2-git-send-email-thor.thayer@linux.intel.com