logprint: handle split EFI entry

logprint: handle split EFI entry

xfs_logprint does not correctly handle EFI entries that
are split across two log buffers. xfs_efi_copy_format()
falsely interrupts the truncated size of the split entry
as being a corrupt entry.

If the first log entry has enough information, namely the
number of extents in the entry and the identifier, then
display this information and a warning that this entry is
truncated. Otherwise, if there is not enough information in
the first log buffer, then print a message that the EFI decode
was not possible. These messages are similar to split inode
entries.

Example of a continued entry:
Oper (336): tid: f214bdb  len: 44  clientid: TRANS  flags: CONTINUE
EFI:  #regs: 1    num_extents: 2  id: 0xffff880804f63900
EFI free extent data skipped (CONTINUE set, no space)

Reported-by: Michael L. Semon <mlsemon35@gmail.com>
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>