RISC-V supports unaligned accesses, therefore enable it

Upstream-Status: Pending
Signed-off-by: Khem Raj <raj.khem@gmail.com>
--- a/m4/as-unaligned-access.m4
+++ b/m4/as-unaligned-access.m4
@@ -5,7 +5,7 @@ AC_DEFUN([AS_UNALIGNED_ACCESS], [
   AC_MSG_CHECKING([if unaligned memory access works correctly])
   if test x"$as_cv_unaligned_access" = x ; then
     case $host in
-      alpha*|arm*|hp*|mips*|sh*|sparc*|ia64*)
+      alpha*|arm*|hp*|mips*|riscv*|sh*|sparc*|ia64*)
         _AS_ECHO_N([(blacklisted) ])
         as_cv_unaligned_access=no
 	;;