Since #7773 caused a build error for `mxss:default`, I made similar changes to 'keyboards/mxss/rgblight.h' as #7773 did to 'quantum/rgblight.h'.
**This commit does not change the build result.**
Testing script
```shell
# build on versions earlier than PR #7773
git checkout 0.8.24
echo master > /tmp/master_md5.txt
make mxss:default:clean
make mxss:default
md5 mxss_default.hex >> /tmp/master_md5.txt
# build on this commit
git checkout fix-keyboards-mxss-rgblight.h
echo fix-keyboards-mxss-rgblight.h > /tmp/branch_md5.txt
make mxss:default:clean
make mxss:default
md5 mxss_default.hex >> /tmp/branch_md5.txt
diff -u /tmp/master_md5.txt /tmp/branch_md5.txt
```
Test result:
```
--- /tmp/master_md5.txt 2020-03-12 05:51:39.000000000 +0900
+++ /tmp/branch_md5.txt 2020-03-12 05:51:49.000000000 +0900
@@ -1,2 +1,2 @@
-master
+fix-keyboards-mxss-rgblight.h
MD5 (mxss_default.hex) = 3034b2504d0c7fc6bd8bf1dffb6b8486
```
* Add VIA support to mxss and general cleanup
* Add support for RGB test for FLEDs
* Add LAYOUT_all to allow for more configuration
* Remove blank layers
* Updated readme
* Improve use of EEPROM
* Credit where its due
* Use the latest iteration of rgblight code
* Keep the RGB timer running if the front LED is in RGB mode
* Fix RGB breathing animation
* Better supported RGB animation
Only thing not working is alternating, but that's not too important
* Abstract front LED handlers from main kb code
* Add support for indicator LED color changing
* Remove debug statement
* Persist indicator LED colors
* Mark custom sections in rgblight.c
* Light commenting
* Fix up keymaps
* Add/update comments
* Remove bloat from default hex
* Tidy a stray tab
* Out with the old, in with the new
* Out with the old, in with the new
* Add LAYER_STATE_8BIT for VIA keymap
This PR is cherry-pick from 90b9a1aa7d in PR #5020.
@MxBlu copied quantum/rgblight.c to keyboards/mxss/rgblight.c on July 8, 2018. At that time, I think it would be better to copy quantum/rgblight.h at the same time.
Because if someone makes a change to `quantum/rgblight.[ch]` that is incompatible with the past, it may cause problems with the compilation of keyboards/mxss.
(Like when I changed the prototype of the `rgblight_effect_XXX()` functions of rgblight.c in PR #5020.)
