gpio: regmap: fix kernel-doc notation

Add a ':' to the end of struct member names to prevent kernel-doc
warnings:

Warning: include/linux/gpio/regmap.h:108 struct member 'regmap_irq_line'
 not described in 'gpio_regmap_config'
Warning: include/linux/gpio/regmap.h:108 struct member 'regmap_irq_flags'
 not described in 'gpio_regmap_config'

Fixes: 553b75d ("gpio: regmap: Allow to allocate regmap-irq device")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20251128062739.845403-1-rdunlap@infradead.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: rddunlap

include/linux/gpio/regmap.h

@@ -50,8 +50,8 @@ struct regmap;
  * @regmap_irq_chip:	(Optional) Pointer on an regmap_irq_chip structure. If
  *			set, a regmap-irq device will be created and the IRQ
  *			domain will be set accordingly.
- * @regmap_irq_line	(Optional) The IRQ the device uses to signal interrupts.
- * @regmap_irq_flags	(Optional) The IRQF_ flags to use for the interrupt.
+ * @regmap_irq_line:	(Optional) The IRQ the device uses to signal interrupts.
+ * @regmap_irq_flags:	(Optional) The IRQF_ flags to use for the interrupt.
  *
  * The ->reg_mask_xlate translates a given base address and GPIO offset to
  * register and mask pair. The base address is one of the given register