leds: qpnp-haptics: Update DT bindings documentation

Description for "qcom,lra-auto-mode" property is missed out and
"qcom,wave-samples" needs to be updated. Update it.

Change-Id: I507634e1323400bd9a48e73425a7e437a46aa1a1
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>