riscv: Remove now superfluous sentinel element from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/[e-mail]/)

Remove sentinel element from riscv_v_default_vstate_table. This removal
is safe because register_sysctl implicitly uses ARRAY_SIZE() in addition
to checking for the sentinel.

Signed-off-by: Joel Granados <[e-mail]>
Signed-off-by: Luis Chamberlain <[e-mail]>

arch/riscv/kernel/vector.c

···
 		.mode		= 0644,
 		.proc_handler	= proc_dobool,
 	},
-	{ }
 };
 
 static int __init riscv_v_sysctl_init(void)