[gdb/symtab] Fix wrong unit_type Dwarf Error

[gdb/symtab] Fix wrong unit_type Dwarf Error

When running test-case gdb.dwarf2/fission-mix.exp using gcc-11 (and using the
tentative fix for PR27353 to get past that assertion failure), I run into:
...
(gdb) file fission-mix^M
Reading symbols from fission-mix...^M
Dwarf Error: wrong unit_type in compilation unit header \
  (is DW_UT_split_compile (0x05), should be DW_UT_type (0x02)) \
  [in module fission-mix2.dwo]^M
(No debugging symbols found in fission-mix)^M
...

The compilation unit that is complained about is:
...
Contents of the .debug_info.dwo section (loaded from fission-mix2.dwo):

  Compilation Unit @ offset 0x0:
   Length:        0x57 (32-bit)
   Version:       5
   Unit Type:     DW_UT_split_compile (5)
   Abbrev Offset: 0x0
   Pointer Size:  8
   DWO ID:        0x3e3930d3cc1805df
 <0><14>: Abbrev Number: 1 (DW_TAG_compile_unit)
...

And the dwarf error is triggered here in read_comp_unit_head:
...
        case DW_UT_split_compile:
          if (section_kind != rcuh_kind::COMPILE)
            error (_("Dwarf Error: wrong unit_type in compilation unit header "
                   "(is %s, should be %s) [in module %s]"),
                   dwarf_unit_type_name (cu_header->unit_type),
                   dwarf_unit_type_name (DW_UT_type), filename);
          break;
...
due to passing rcuh_kind::TYPE here in open_and_init_dwo_file:
...
      create_debug_type_hash_table (per_objfile, dwo_file.get (),
                                    &dwo_file->sections.info, dwo_file->tus,
                                    rcuh_kind::TYPE);
...

Fix this by changing the section_kind argument to create_debug_type_hash_table
to rcuh_kind::COMPILE, to reflect that we're passing &dwo_file->sections.info
rather than &dwo_file->sections.types.

Tested on x86_64-linux.

gdb/ChangeLog:

2021-02-25  Tom de Vries  <tdevries@suse.de>

	PR symtab/27354
	* dwarf2/read.c (open_and_init_dwo_file): Use rcuh_kind::COMPILE as
	section_kind for &dwo_file->sections.info.