net: dsa: mxl862xx: move API macros to mxl862xx-host.h

net: dsa: mxl862xx: move API macros to mxl862xx-host.h

Move the MXL862XX_API_WRITE, MXL862XX_API_READ and
MXL862XX_API_READ_QUIET convenience macros from mxl862xx.c to
mxl862xx-host.h next to the mxl862xx_api_wrap() prototype they wrap.
This makes them available to other compilation units that include
mxl862xx-host.h, which is needed once the SerDes PCS code in
mxl862xx-phylink.c also calls firmware commands.

No functional change.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/914f57931e79cc3932a9f32813465c08d29cf4bf.1781319534.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>