efl_access: if 0 is set as reading_info_type, remove existing reading_info

efl_access: if 0 is set as reading_info_type, remove existing reading_info

Summary:
if 0 is set as reading_info_type, remove existing reading_info and
allow default reading info types (name, role, state and description)
to be read.
Do not set reading info again in reading_info_type_set API if new
value matches the old value.

Test Plan:
If application does not set reading_info_type or set 0 reading_info_type,
All four reading info types of an accessible object should be read on highlight.

Signed-off-by: Shilpa Singh <shilpa.singh@samsung.com>
Reviewers: kimcinoo, jsuya, bu5hm4n, lukasz.stanislawski

Subscribers: prasoonsingh16, rajeev.jnnce, #reviewers, cedric, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D8435

Change-Id: I5258ad5c6a1210c4880aa822ed1c504cf838b8ca