arm64: dts: ti: k3-am64-main: Fix the clock ID for rng node

Fix the clock ID for rng node. It uses DEV_SA2_UL0_X1_CLK,
not DEV_SA2_UL0_PKA_IN_CLK.

Fixes: f54c8007

 ('arm64: dts: ti: k3-am64-main: Enable
 crypto accelerator')
Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>