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.org


Signed-off-by: Lee Jones <lee@kernel.org>