Convert f072 backlight build error to message (#8177)

docs/feature_backlight.md

@@ -167,7 +167,7 @@ BACKLIGHT_DRIVER = pwm
 
 Currently only hardware PWM is supported, not timer assisted, and does not provide automatic configuration.
 
-?> STMF072 support is being investigated.
+?> Backlight support for STMF072 has had limited testing, YMMV. If unsure, set `BACKLIGHT_ENABLE = no` in your rules.mk.
 
 ### ARM Configuration
 

quantum/backlight/backlight_arm.c

@@ -7,7 +7,7 @@
 #ifdef BACKLIGHT_PIN
 
 #    if defined(STM32F0XX) || defined(STM32F0xx)
-#        error "Backlight support for STMF072 is not available. Please disable."
+#        pragma message("Backlight support for STMF072 has had limited testing, YMMV. If unsure, set 'BACKLIGHT_ENABLE = no' in your rules.mk")
 #    endif
 
 // GPIOV2 && GPIOV3