FTL: Extend enum utilities imported from IF

Generalize compile-time and run-time lookup of enumerator names by
recognizing ftl_first and ftl_last to customize the range.

Add enum_range<E>() for iteration using range-based `for` loop.

Bug: 185536303
Test: Check assembly for small LUT in .rodata, and unrolled loops.
Test: ftl_test, libinput_tests, inputflinger_tests
Test: m libinputflinger
Change-Id: I0581611f4cfcf5837b0293867cb323742afb2c87
diff --git a/services/inputflinger/reader/include/EventHub.h b/services/inputflinger/reader/include/EventHub.h
index 7a00bac..1f96294 100644
--- a/services/inputflinger/reader/include/EventHub.h
+++ b/services/inputflinger/reader/include/EventHub.h
@@ -146,6 +146,8 @@
 enum class SysfsClass : uint32_t {
     POWER_SUPPLY = 0,
     LEDS = 1,
+
+    ftl_last = LEDS
 };
 
 enum class LightColor : uint32_t {