target/arm: Rename sve_zcr_len_for_el to sve_vqm1_for_el

This will be used for both Normal and Streaming SVE, and the value
does not necessarily come from ZCR_ELx.  While we're at it, emphasize
the units in which the value is returned.

Patch produced by
    git grep -l sve_zcr_len_for_el | \
    xargs -n1 sed -i 's/sve_zcr_len_for_el/sve_vqm1_for_el/g'

and then adding a function comment.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220607203306.657998-13-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 73f24a5..e45b5cb 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -1132,7 +1132,16 @@
 
 int fp_exception_el(CPUARMState *env, int cur_el);
 int sve_exception_el(CPUARMState *env, int cur_el);
-uint32_t sve_zcr_len_for_el(CPUARMState *env, int el);
+
+/**
+ * sve_vqm1_for_el:
+ * @env: CPUARMState
+ * @el: exception level
+ *
+ * Compute the current SVE vector length for @el, in units of
+ * Quadwords Minus 1 -- the same scale used for ZCR_ELx.LEN.
+ */
+uint32_t sve_vqm1_for_el(CPUARMState *env, int el);
 
 static inline bool is_a64(CPUARMState *env)
 {