misc: Update README_SVE.md (RDFFR(S), WRFFR, SETFFR)

Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>

README_SVE.md

diff --git a/README_SVE.md b/README_SVE.md
index 02d6653..b20ba1b 100644
--- a/README_SVE.md
+++ b/README_SVE.md
@@ -47,14 +47,10 @@
     - INSR (SIMD&FP scalar)
     - LASTA (SIMD&FP scalar)
     - LASTB (SIMD&FP scalar)
-    - RDFFR (unpredicated)
-    - RDFFR, RDFFRS (predicated)
     - SDOT (indexed)
     - SDOT (vectors)
-    - SETFFR
     - UDOT (indexed)
     - UDOT (vectors)
-    - WRFFR
 
 Work is currently ongoing on the implementation of the instructions above, and
 priority is given to instructions that are more likely to be emitted by a