pmdomain: core: Harden inter-column space in debug summary

The inter-column space in the debug summary is two spaces.  However, in
one case, the extra space is handled implicitly in a field width
specifier.  Make inter-column space explicit to ease future maintenance.

Fixes: 45fbc464 ("PM: domains: Add "performance" column to debug summary")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/ae61eb363621b981edde878e1e74d701702a579f.1725459707.git.geert+renesas@glider.be


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>