docs: bpf: get rid of two warnings

Documentation/bpf/btf.rst:154: WARNING: Unexpected indentation.
Documentation/bpf/btf.rst:163: WARNING: Unexpected indentation.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/bpf/btf.rst

@@ -151,6 +151,7 @@ for the type. The maximum value of ``BTF_INT_BITS()`` is 128.
 
 The ``BTF_INT_OFFSET()`` specifies the starting bit offset to calculate values
 for this int. For example, a bitfield struct member has:
+
  * btf member bit offset 100 from the start of the structure,
  * btf member pointing to an int type,
  * the int type has ``BTF_INT_OFFSET() = 2`` and ``BTF_INT_BITS() = 4``
@@ -160,6 +161,7 @@ from bits ``100 + 2 = 102``.
 
 Alternatively, the bitfield struct member can be the following to access the
 same bits as the above:
+
  * btf member bit offset 102,
  * btf member pointing to an int type,
  * the int type has ``BTF_INT_OFFSET() = 0`` and ``BTF_INT_BITS() = 4``