Currently, fdt_path_offset() returns FDL_ERR_BADOFFSET if given a path
with a trailing '/'. In particular this means that
fdt_path_offset("/") returns FDT_ERR_BADOFFSET rather than 0 as one
would expect.
This patch fixes the function to accept and ignore trailing '/'
characters. As well as allowing fdt_path_offset("/") this means that
fdt_path_offset("/foo/") will return the same as
fdt_path_offset("/foo") which seems in keeping with the principle of
least surprise.
This also adds a testcase to ensure that fdt_path_offset("/") returns
0 as it should.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>