[builtins] Fix floattitf.c etc. compilation on Solaris/SPARC (#70058)

69660cc broke the [Solaris/sparcv9
buildbot](https://lab.llvm.org/staging/#/builders/12/builds/264):
`compiler-rt/lib/builtins/int_to_fp.h` unconditionally uses `*int128_t`
which don't exist on 32-bit SPARC.

As suggested in #67540, this
patch fixes this by moving the `CRT_HAS_TF_MODE` guard up which does the
necessary checks.

Tested on `sparcv9-sun-solaris2.11`.

Author: rorth

compiler-rt/lib/builtins/floattitf.c

@@ -16,6 +16,7 @@
 #include "fp_lib.h"
 #include "int_lib.h"
 
+#if defined(CRT_HAS_TF_MODE)
 #define SRC_I128
 #define DST_QUAD
 #include "int_to_fp_impl.inc"
@@ -29,7 +30,6 @@
 // mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm
 // mmmm mmmm mmmm
 
-#if defined(CRT_HAS_TF_MODE)
 COMPILER_RT_ABI fp_t __floattitf(ti_int a) { return __floatXiYf__(a); }
 
 #endif

compiler-rt/lib/builtins/floatuntitf.c

@@ -16,6 +16,7 @@
 #include "fp_lib.h"
 #include "int_lib.h"
 
+#if defined(CRT_HAS_TF_MODE)
 #define SRC_U128
 #define DST_QUAD
 #include "int_to_fp_impl.inc"
@@ -29,7 +30,6 @@
 // mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm
 // mmmm mmmm mmmm
 
-#if defined(CRT_HAS_TF_MODE)
 COMPILER_RT_ABI fp_t __floatuntitf(tu_int a) { return __floatXiYf__(a); }
 
 #endif