dt-bindings: i2c: adds two more nxp devices

"nxp,pcf2127" and "nxp,pcf2129" are I2c devices, adds them to the list
of trivial i2c devices.

Signed-off-by: Shaohui Xie <Shaohui.Xie@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Documentation/devicetree/bindings/i2c/trivial-devices.txt

@@ -130,6 +130,8 @@ nuvoton,npct501		i2c trusted platform module (TPM)
 nuvoton,npct601		i2c trusted platform module (TPM2)
 nxp,pca9556		Octal SMBus and I2C registered interface
 nxp,pca9557		8-bit I2C-bus and SMBus I/O port with reset
+nxp,pcf2127		Real-time clock
+nxp,pcf2129		Real-time clock
 nxp,pcf8563		Real-time clock/calendar
 nxp,pcf85063		Tiny Real-Time Clock
 oki,ml86v7667		OKI ML86V7667 video decoder