backlight: ili922x: Drop kernel-doc for local macros

Don't use kernel-doc notation for the local macros START_BYTE() and
CHECK_FREQ_REG(). This prevents these kernel-doc warnings:

ili922x.c:85: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * START_BYTE(id, rs, rw)
ili922x.c:85: warning: missing initial short description on line:
 * START_BYTE(id, rs, rw)
ili922x.c:118: warning: expecting prototype for CHECK_FREQ_REG(spi_device s, spi_transfer x)(). Prototype was for CHECK_FREQ_REG() instead
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20231206174525.14960-1-rdunlap@infradead.orgSigned-off-by: Lee Jones <lee@kernel.org>

drivers/video/backlight/ili922x.c

@@ -81,7 +81,7 @@
 #define START_RW_WRITE		0
 #define START_RW_READ		1
 
-/**
+/*
  * START_BYTE(id, rs, rw)
  *
  * Set the start byte according to the required operation.
@@ -100,7 +100,7 @@
 #define START_BYTE(id, rs, rw)	\
 	(0x70 | (((id) & 0x01) << 2) | (((rs) & 0x01) << 1) | ((rw) & 0x01))
 
-/**
+/*
  * CHECK_FREQ_REG(spi_device s, spi_transfer x) - Check the frequency
  *	for the SPI transfer. According to the datasheet, the controller
  *	accept higher frequency for the GRAM transfer, but it requires