pinctrl: st: Drop wrong kernel doc annotations

Kernel doc validator is not happy:

  .../pinctrl-st.c:59: warning: This comment starts with '/**', but isn't a kernel-doc comment.
  .../pinctrl-st.c:73: warning: This comment starts with '/**', but isn't a kernel-doc comment.

Drop them as they are indeed not a kernel doc comments.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-st.c

@@ -55,7 +55,7 @@
 #define ST_GPIO_DIRECTION_OUT	0x2
 #define ST_GPIO_DIRECTION_IN	0x4
 
-/**
+/*
  *  Packed style retime configuration.
  *  There are two registers cfg0 and cfg1 in this style for each bank.
  *  Each field in this register is 8 bit corresponding to 8 pins in the bank.
@@ -69,7 +69,7 @@
 #define RT_P_CFG1_CLKNOTDATA_FIELD(reg)		REG_FIELD(reg, 16, 23)
 #define RT_P_CFG1_DOUBLE_EDGE_FIELD(reg)	REG_FIELD(reg, 24, 31)
 
-/**
+/*
  * Dedicated style retime Configuration register
  * each register is dedicated per pin.
  */