Adding support of Numpad Enter Key in text fields.

This patch adds correct handling of Numpad Enter Key for
text fields widget. Before it was shown as 'space' but not
as the end of input.

Change-Id: Ic67fa8a7f96a1332420db082e2c8c6824c316a2b
Signed-off-by: Dmytro Dubovyk <x0185493@ti.com>