Remove extra dot from depreceation, obsoletion warnings

Remove extra dot from depreceation and obsoletion warnings to be consistent.
Changes
 x: warning: BOARD_PLAT_PUBLIC_SEPOLICY_DIR has been deprecated. Use SYSTEM_EXT_PUBLIC_SEPOLICY_DIRS instead..
to
 x: warning: BOARD_PLAT_PUBLIC_SEPOLICY_DIR has been deprecated. Use SYSTEM_EXT_PUBLIC_SEPOLICY_DIRS instead.

Test: m
Change-Id: I60a4258e549570e261252cffee69e5640f62295e
Signed-off-by: Timi <timi.rautamaki@gmail.com>