[SWDEV-324968] - Fixes libffi cmake issue on centos/sles.

Recently, a change was introduced where the cmake
searches for libffi.a to fix versioning issues
with 18.04/20.04. There is no libffi static archive
on centos/sles so we need to add ffi as a fallback
in order to find libff.so.

Change-Id: Ia684e48fc19de4d9769e83d5fbfc26ece9e6db88

Author: estewart08

openmp/libomptarget/cmake/Modules/LibomptargetGetDependencies.cmake

@@ -116,6 +116,7 @@ if (LIBOMPTARGET_DEP_LIBFFI_INCLUDE_DIR)
       LIBOMPTARGET_DEP_LIBFFI_LIBRARIES
     NAMES
       libffi.a
+      ffi
     HINTS
       ${LIBOMPTARGET_SEARCH_LIBFFI_LIBDIR}
       ${LIBOMPTARGET_SEARCH_LIBFFI_LIBRARY_DIRS}