microblaze: Add link options to dl07, dl08, and dl09

This adds `-u__extendsfdf2` to the `ldflags` for the dl07, dl08, and
dl09 tests to force the inclusion of `__extendsfdf2` in the base image.
This function is part of the GCC software floating point library and is
used in the tests to convert floats to doubles when calling `printf`.

spec/build/testsuites/libtests/dl07.yml

@@ -33,7 +33,10 @@ enabled-by:
   - BUILD_LIBDL
 includes:
 - testsuites/libtests/dl07
-ldflags: []
+ldflags:
+- enabled-by:
+  - microblaze
+  value: -u__extendsfdf2
 links: []
 prepare-build: null
 prepare-configure: null

spec/build/testsuites/libtests/dl08.yml

@@ -38,7 +38,10 @@ enabled-by:
   - BUILD_LIBDL
 includes:
 - testsuites/libtests/dl08
-ldflags: []
+ldflags:
+- enabled-by:
+  - microblaze
+  value: -u__extendsfdf2
 links: []
 prepare-build: null
 prepare-configure: null

spec/build/testsuites/libtests/dl09.yml

@@ -33,7 +33,10 @@ enabled-by:
   - BUILD_LIBDL
 includes:
 - testsuites/libtests/dl09
-ldflags: []
+ldflags:
+- enabled-by:
+  - microblaze
+  value: -u__extendsfdf2
 links: []
 prepare-build: null
 prepare-configure: null