[0.2.116] mm_attrs: Export API set located in mm_attrs_private.h

[0.2.116] mm_attrs: Export API set located in mm_attrs_private.h

libmm-xxx libraries commonly use some functions in mm_attrs_private.h
directly. Therefore, it seems there isn't much meaning for the existence
of these functions in private header file any more. This patch exports
these private API set with 'mm_' prefix to mm_attrs.h.

Added to mm_attrs.h as below:
 MMAttrsValue
 MMAttrsConstructInfo
 mm_attrs_commit_callback
 mm_attrs_new()
 mm_attrs_free()
 mm_attrs_commit()
 mm_attrs_commit_all()
 mm_attrs_set_valid_type()
 mm_attrs_set_valid_range()
 mm_attrs_set_valid_array()
 mm_attrs_set_valid_double_range()
 mm_attrs_set_valid_double_array()
 mm_attrs_is_modified()
 mm_attrs_set_modified()
 mm_attrs_set_readonly()
 mm_attrs_set_disabled()

Note that the following patch will hide the private header file from
devel package soon after using these new API set instead of former ones
in libmm-xxx libraries.

Change-Id: I6c60f512a6c34ed1108c44fab5bb820af9570f49
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>