target/arm: Rename TBFLAG_A64 ZCR_LEN to VL

With SME, the vector length does not only come from ZCR_ELx.
Comment that this is either NVL or SVL, like the pseudocode.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220607203306.657998-2-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 0ee1705..e791ffdd 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -3241,7 +3241,8 @@
  */
 FIELD(TBFLAG_A64, TBII, 0, 2)
 FIELD(TBFLAG_A64, SVEEXC_EL, 2, 2)
-FIELD(TBFLAG_A64, ZCR_LEN, 4, 4)
+/* The current vector length, either NVL or SVL. */
+FIELD(TBFLAG_A64, VL, 4, 4)
 FIELD(TBFLAG_A64, PAUTH_ACTIVE, 8, 1)
 FIELD(TBFLAG_A64, BT, 9, 1)
 FIELD(TBFLAG_A64, BTYPE, 10, 2)         /* Not cached. */