arm64/sme: Fix cut'n'paste in ABI document

The ABI for SME is very like that for SVE so bits of the ABI were copied
but not adequately search and replaced, fix that.

Reported-by: Edmund Grimley-Evans <edmund.grimley-evans@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20240124-arm64-sve-sme-doc-v2-2-fe3964fb3c19@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: broonie

Documentation/arch/arm64/sme.rst

@@ -238,12 +238,12 @@ prctl(PR_SME_SET_VL, unsigned long arg)
       bits of Z0..Z31 except for Z0 bits [127:0] .. Z31 bits [127:0] to become
       unspecified, including both streaming and non-streaming SVE state.
       Calling PR_SME_SET_VL with vl equal to the thread's current vector
-      length, or calling PR_SME_SET_VL with the PR_SVE_SET_VL_ONEXEC flag,
+      length, or calling PR_SME_SET_VL with the PR_SME_SET_VL_ONEXEC flag,
       does not constitute a change to the vector length for this purpose.
 
     * Changing the vector length causes PSTATE.ZA and PSTATE.SM to be cleared.
       Calling PR_SME_SET_VL with vl equal to the thread's current vector
-      length, or calling PR_SME_SET_VL with the PR_SVE_SET_VL_ONEXEC flag,
+      length, or calling PR_SME_SET_VL with the PR_SME_SET_VL_ONEXEC flag,
       does not constitute a change to the vector length for this purpose.