xen/arm: Introduce a wrapper for dt_device_get_address() to handle paddr_t

xen/arm: Introduce a wrapper for dt_device_get_address() to handle paddr_t

dt_device_get_address() can accept uint64_t only for address and size.
However, the address/size denotes physical addresses. Thus, they should
be represented by 'paddr_t'.
Consequently, we introduce a wrapper for dt_device_get_address() ie
dt_device_get_paddr() which accepts address/size as paddr_t and inturn
invokes dt_device_get_address() after converting address/size to
uint64_t.

The reason for introducing this is that in future 'paddr_t' may not
always be 64-bit. Thus, we need an explicit wrapper to do the type
conversion and return an error in case of truncation.

With this, callers can now invoke dt_device_get_paddr(). However, ns16550.c
is left unchanged as it requires some prior cleanup. For details, see
https://patchew.org/Xen/20230413173735.48387-1-ayan.kumar.halder@amd.com.
This will be addressed in a subsequent series.

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Acked-by: Julien Grall <jgrall@amazon.com>