hmp: fix info cpus for sparc targets

hmp: fix info cpus for sparc targets

On sparc targets, info cpus returns this kind of output:

| info cpus
| * CPU #0: pc=0x0000000000424d18pc=0x0000000000424d18npc=0x0000000000424d1c thread_id=19460

pc is printed twice, there is no space between pc, pc and npc.

With this patch, pc is not printed anymore when has_npc is set. In addition
the space is printed before pc/nip/npc/PC instead of after the colon so that
multiple prints are possible. This result on the following kind of input on
sparc targets:

| info cpus
| * CPU #0: pc=0x0000000000424d18 npc=0x0000000000424d1c thread_id=19460

Cc: Luiz Capitulino <[email protected]>
Cc: Markus Armbruster <[email protected]>
Cc: Blue Swirl <[email protected]>
Signed-off-by: Aurelien Jarno <[email protected]>
Signed-off-by: Luiz Capitulino <[email protected]>