Fix some definitions on AVR target

[LittleFox94]

Summary

Fix definitions in AVR target for MCUs xmega16a4u and xmega128a4u to match avr-libc.

[LittleFox94]

I guess this would have qualified for post-commit review, but since this would have been my first commit I made myself, I want to be careful ^^
Comments on this would be nice, if this would have been ok to just commit.

[xgupta]

Thanks!

ref - https://www.microchip.com/en-us/product/ATxmega16A4U

[LittleFox94]

This is committed by now, but I would still love to know if this would have been ok to just commit (and have post-commit review) :)

[xgupta]

Yeah, Such patches are OK to commit by just adding a [NFC] tag in commit message. Though if you spend some time on Phabricator, you will be aware of which kind of patches need reviews and which can be committed directly.

clang/lib/Basic/Targets/AVR.cpp

static MCUInfo AVRMcus[] = {
     {"at90can128", "__AVR_AT90CAN128__"},
     {"at90usb1286", "__AVR_AT90USB1286__"},
     {"at90usb1287", "__AVR_AT90USB1287__"},
     {"atmega2560", "__AVR_ATmega2560__"},
     {"atmega2561", "__AVR_ATmega2561__"},
     {"atmega256rfr2", "__AVR_ATmega256RFR2__"},
     {"atmega2564rfr2", "__AVR_ATmega2564RFR2__"},
     {"atxmega16a4", "__AVR_ATxmega16A4__"},
-    {"atxmega16a4u", "__AVR_ATxmega16a4U__"},
+    {"atxmega16a4u", "__AVR_ATxmega16A4U__"},
     {"atxmega16c4", "__AVR_ATxmega16C4__"},
     {"atxmega16d4", "__AVR_ATxmega16D4__"},
     {"atxmega32a4", "__AVR_ATxmega32A4__"},
     {"atxmega32a4u", "__AVR_ATxmega32A4U__"},
     {"atxmega32c4", "__AVR_ATxmega32C4__"},
     {"atxmega32d4", "__AVR_ATxmega32D4__"},
     {"atxmega32e5", "__AVR_ATxmega32E5__"},
     {"atxmega16e5", "__AVR_ATxmega16E5__"},
static MCUInfo AVRMcus[] = {
     {"atxmega256a3b", "__AVR_ATxmega256A3B__"},
     {"atxmega256a3bu", "__AVR_ATxmega256A3BU__"},
     {"atxmega256c3", "__AVR_ATxmega256C3__"},
     {"atxmega256d3", "__AVR_ATxmega256D3__"},
     {"atxmega384c3", "__AVR_ATxmega384C3__"},
     {"atxmega384d3", "__AVR_ATxmega384D3__"},
     {"atxmega128a1", "__AVR_ATxmega128A1__"},
     {"atxmega128a1u", "__AVR_ATxmega128A1U__"},
-    {"atxmega128a4u", "__AVR_ATxmega128a4U__"},
+    {"atxmega128a4u", "__AVR_ATxmega128A4U__"},
     {"attiny4", "__AVR_ATtiny4__"},
     {"attiny5", "__AVR_ATtiny5__"},
     {"attiny9", "__AVR_ATtiny9__"},
     {"attiny10", "__AVR_ATtiny10__"},
     {"attiny20", "__AVR_ATtiny20__"},
     {"attiny40", "__AVR_ATtiny40__"},
     {"attiny102", "__AVR_ATtiny102__"},
     {"attiny104", "__AVR_ATtiny104__"},