radix tree test suite: Fix damage by separation of gfp and gfp_types

radix tree test suite: Fix damage by separation of gfp and gfp_types

When the gfp header was split into two for a much smaller header, it
broke the radix test suite.  Fix the test suite by splitting the header
in the test suite as well.

Fixes: cb5a065b4ea9 (headers/deps: mm: Split <linux/gfp_types.h> out of <linux/gfp.h>)
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Yury Norov <yury.norov@gmail.com>