tools: testing: fix phys_addr_t size on 64-bit systems

tools: testing: fix phys_addr_t size on 64-bit systems

The phys_addr_t size is predicated on whether CONFIG_PHYS_ADDR_T_64BIT is
set or not.

In the VMA tests, virt_to_phys() from tools/include/linux casts a volatile
void * pointer to phys_addr_t, if CONFIG_PHYS_ADDR_T_64BIT is not set,
this will be 32-bit and trigger a warning.

Obviously this might also lead to truncation, which we would rather avoid.

Fix this by adjusting the generation of generated/bit-length.h to generate
a CONFIG_PHYS_ADDR_T{bits}BIT define.

This does result in the generation of the useless CONFIG_PHYS_ADDR_T_32BIT
define for 32-bit systems, but this should have no effect, and makes
implementation of this easier.

This resolves the issue and the warning.

Link: https://lkml.kernel.org/r/20241017165638.95602-1-lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Tested-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>