CPUID: Implement support for XCR0 when AVX is enabled

This enables AVX, AVX2, FMA3 for the entire CPUID!

```bash
$ FEX_HOSTFEATURES=enableavx,enableavx2 ./Bin/FEXInterpreter /usr/bin/cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Cortex-A78AE
stepping        : 0
microcode       : 0x0
cpu MHz         : 3000
cache size      : 512 KB
physical id     : 0
siblings        : 12
core id         : 0
cpu cores       : 12
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 22
wp              : yes
flags           : fpu vme tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht tm syscall nx mmxext fxsr_opt rdtscp lm 3dnow 3dnowext constant_tsc art rep_good nopl xtoplogy nonstop_tsc cpuid tsc_known_freq pni pclmulqdq dtes64 monitor tm2 ssse3 fma cx16 sse4_1 sse4_2 movbe popcnt aes xsave avx hypervisor lahf_lm cmp_legacy extapic abm 3dnowprefetc
h tce fsgsbase bmi1 avx2 smep bmi2 erms invpcid adx clflushopt clwb sha_ni clzero arat vpclmulqdq rdpid fsrm
bugs            :
bogomips        : 8000.0
TLB size        : 2560 4K pages
clflush size    : 64
cache_alignment  : 64
address sizes   : 40 bits physical, 48 bits virtual
power management:
```

Notice avx, avx2, and fma

FEXCore/Source/Interface/Core/CPUID.cpp

@@ -347,8 +347,7 @@ void CPUIDEmu::SetupHostHybridFlag() {}
 
 
 void CPUIDEmu::SetupFeatures() {
-  // TODO: Enable once AVX is supported.
-  if (false && CTX->HostFeatures.SupportsAVX) {
+  if (CTX->HostFeatures.SupportsAVX) {
     XCR0 |= XCR0_AVX;
   }