bug/x86/arm: Align bug_frames sections.

bug/x86/arm: Align bug_frames sections.

Most of the WARN_ON or BUG_ON sections are properly aligned on
x86. However on ARM and on x86 assembler the macros don't include
any alignment information - hence they end up being the default
byte granularity.

On ARM32 it is paramount that the alignment is word-size (4)
otherwise if one tries to use (uint32_t*) access (such
as livepatch ELF relocations) we get a Data Abort.

Enforcing bug_frames to have the proper alignment across all
architectures and in both C and x86 makes them all the same.

Furthermore on x86 the bloat-o-meter detects that with this
change:

add/remove: 0/0 grow/shrink: 0/0 up/down: 0/0 (0)
function                                     old     new   delta

On ARM32:
add/remove: 1/0 grow/shrink: 0/1 up/down: 384/-288 (96)
function                                     old     new   delta
gnttab_unpopulate_status_frames                -     384    +384
do_grant_table_op                          10808   10520    -288

And ARM64:
add/remove: 1/2 grow/shrink: 0/1 up/down: 4164/-4236 (-72)
function                                     old     new   delta
gnttab_map_grant_ref                           -    4164   +4164
do_grant_table_op                           9892    9836     -56
grant_map_exists                             300       -    -300
__gnttab_map_grant_ref                      3880       -   -3880

Reviewed-by: Julien Grall <julien.grall@arm.com>
Acked-by: Jan Beulich <jbeulich@suse.com> [x86 parts]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>