Add support for LZO compression in GRUB:

Add support for LZO compression in GRUB:
- import of minilzo library,
- LZO decompression for btrfs,
- lzop files decompression.

* grub-core/io/lzopio.c: New file.
* grub-core/lib/adler32.c: Likewise.
* grub-core/lib/minilzo/lzoconf.h: Likewise.
* grub-core/lib/minilzo/lzodefs.h: Likewise.
* grub-core/lib/minilzo/minilzo.c: Likewise.
* grub-core/lib/minilzo/minilzo.h: Likewise.
* Makefile.util.def (libgrubmods.a): Add grub-core/io/lzopio.c,
grub-core/lib/adler32.c, grub-core/io/lzopio.c,
grub-core/lib/minilzo/minilzo.c to common.
* Makefile.util.def (libgrubmods.a): Add flags required by minilzo to
cflags in cppflags.
* grub-core/Makefile.core.def (btrfs): Likewise.
* grub-core/Makefile.core.def (lzopio): New module.
(adler32): Likewise.
* grub-core/fs/btrfs.c: Include minilzo.h.
(GRUB_BTRFS_COMPRESSION_LZO): New define.
(GRUB_BTRFS_LZO_BLOCK_SIZE): Likewise.
(GRUB_BTRFS_LZO_BLOCK_MAX_CSIZE): Likewise.
(grub_btrfs_lzo_decompress): New function.
(grub_btrfs_extent_read): Add support for LZO compression type.
* include/grub/types.h (GRUB_UCHAR_MAX): New define.
(GRUB_USHRT_MAX): Likewise.
(GRUB_UINT_MAX): Likewise.
* grub-core/lib/posix_wrap/limits.h (USHRT_MAX): Likewise.
(UINT_MAX): Likewise.
(CHAR_BIT): Likewise.
* grub-core/lib/posix_wrap/sys/types.h (ULONG_MAX): Moved to
grub-core/lib/posix_wrap/limits.h
(UCHAR_MAX): Likewise.
* include/grub/file.h (grub_file_filter_id): New compression filter
GRUB_FILE_FILTER_LZOPIO.
* include/grub/file.h (grub_file_filter_id): Set
GRUB_FILE_FILTER_LZOPIO as GRUB_FILE_FILTER_COMPRESSION_LAST.
* include/grub/types.h (grub_get_unaligned16): New function.
(grub_get_unaligned32): Likewise.
(grub_get_unaligned64): Likewise.
* util/import_gcry.py (cryptolist): Add adler32.