sparc: vDSO: remove an extra tab

This statement is indented one tab too far which is confusing and
leads to a Smatch warning:

    arch/sparc/vdso/vma.c:254 arch_setup_additional_pages()
    warn: curly braces intended?

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>