[CMake][compiler-rt] Include the missing variables

This includes the missing variables as pointed out in
https://reviews.llvm.org/rGb0e2ffe151c3

compiler-rt/cmake/crt-config-ix.cmake

@@ -20,8 +20,11 @@ endif()
 
 set(ARM64 aarch64)
 set(ARM32 arm armhf armv6m armv7m armv7em armv7 armv7s armv7k)
+set(HEXAGON hexagon)
 set(X86 i386)
 set(X86_64 x86_64)
+set(PPC32 powerpc powerpcspe)
+set(PPC64 powerpc64 powerpc64le)
 set(RISCV32 riscv32)
 set(RISCV64 riscv64)
 set(VE ve)