xen/arm32: head: Replace load_paddr with adr_l when they are equivalent

xen/arm32: head: Replace load_paddr with adr_l when they are equivalent

Before the MMU is turned on, PC uses physical address. Thus, one can use adr_l
instead of load_paddr to obtain the physical address of a symbol.

The only exception (for this replacement) is create_table_entry() which is
called before and after MMU is turned on.

Also, in lookup_processor_type() "r10" is no longer used. The reason being
__lookup_processor_type uses adr_l (thus r10 is no longer used to obtain the
physical address offset). Consequently, there is no need to save/restore r10.

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
[jgrall: Reword comment on top of __lookup_processor_type]
Signed-off-by: Julien Grall <jgrall@amazon.com>