pinctrl: bcm: pinctrl-bcm281xx: Demote obvious misuse of kerneldoc to standard comment blocks

There has been little to no attempt to document any of the demoted
structures here. These are obviously not kerneldoc headers.

Fixes the following W=1 kernel build warning(s):

drivers/pinctrl/bcm/pinctrl-bcm281xx.c:65: warning: cannot understand function prototype: 'enum bcm281xx_pin_type '
drivers/pinctrl/bcm/pinctrl-bcm281xx.c:79: warning: cannot understand function prototype: 'struct bcm281xx_pin_function '
drivers/pinctrl/bcm/pinctrl-bcm281xx.c:89: warning: cannot understand function prototype: 'struct bcm281xx_pinctrl_data '

Signed-off-by: Lee Jones <[e-mail]>
Acked-by: Scott Branden <[e-mail]>
Cc: Florian Fainelli <[e-mail]>
Cc: Ray Jui <[e-mail]>
Cc: Scott Branden <[e-mail]>
Cc: [e-mail]
Cc: YueHaibing <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/bcm/pinctrl-bcm281xx.c

···
 #define BCM281XX_HDMI_PIN_REG_MODE_MASK		0x0010
 #define BCM281XX_HDMI_PIN_REG_MODE_SHIFT	4
 
-/**
+/*
  * bcm281xx_pin_type - types of pin register
  */
 enum bcm281xx_pin_type {
···
 static enum bcm281xx_pin_type i2c_pin = BCM281XX_PIN_TYPE_I2C;
 static enum bcm281xx_pin_type hdmi_pin = BCM281XX_PIN_TYPE_HDMI;
 
-/**
+/*
  * bcm281xx_pin_function- define pin function
  */
 struct bcm281xx_pin_function {
···
 	const unsigned ngroups;
 };
 
-/**
+/*
  * bcm281xx_pinctrl_data - Broadcom-specific pinctrl data
  * @reg_base - base of pinctrl registers
  */