sparse_init_one_section() is being called from two sites: sparse_init()
and sparse_add_one_section().  The former calls it from a
for_each_present_section_nr() loop, and the latter marks the section as
present before calling it.  This means that when
sparse_init_one_section() gets called, we already know that the section
is present.  So there is no point to double check that in the function.

This removes the check and makes the function void.

[ross.zwisler@linux.intel.com: fix error path in sparse_add_one_section]
  Link: http://lkml.kernel.org/r/20180706190658.6873-1-ross.zwisler@linux.intel.com
[ross.zwisler@linux.intel.com: simplification suggested by Oscar]
  Link: http://lkml.kernel.org/r/20180706223358.742-1-ross.zwisler@linux.intel.com
Link: http://lkml.kernel.org/r/20180702154325.12196-1-osalvador@techadventures.netSigned-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>