powerpc/powernv: Add error handling to opal_prd_range_is_valid

In the opal_prd_range_is_valid function within opal-prd.c,
error handling was missing for the of_get_address call.
This patch adds necessary error checking, ensuring that the
function gracefully handles scenarios where of_get_address fails.

Signed-off-by: Haoran Liu <liuhaoran14@163.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231127144108.29782-1-liuhaoran14@163.com