MAINTAINERS: Limit KVM RISC-V entry to existing selftests

Commit fed9b26b25 ("MAINTAINERS: Update KVM RISC-V entry to cover
selftests support") optimistically adds a file entry for
tools/testing/selftests/kvm/riscv/, but this directory does not exist.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference. The script is very useful to keep MAINTAINERS up to date
and MAINTAINERS can be kept in a state where the script emits no warning.

So, just drop the non-matching file entry rather than starting to collect
exceptions of entries that may match in some close or distant future.

Fixes: fed9b26b25 ("MAINTAINERS: Update KVM RISC-V entry to cover selftests support")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

MAINTAINERS

@@ -10863,7 +10863,6 @@ F:	arch/riscv/include/asm/kvm*
 F:	arch/riscv/include/uapi/asm/kvm*
 F:	arch/riscv/kvm/
 F:	tools/testing/selftests/kvm/*/riscv/
-F:	tools/testing/selftests/kvm/riscv/
 
 KERNEL VIRTUAL MACHINE for s390 (KVM/s390)
 M:	Christian Borntraeger <borntraeger@linux.ibm.com>