PM / domains: Align column headers and data in pm_genpd_summary output

"domain": header is indented by 4, data by 0 spaces => 0 spaces
"/device": header is indented by 11, data by 4 spaces => 4 spaces
"slaves": header is indented by 47, data by 49 spaces => 48 spaces

Ruler:
    1234567890123456789012345678901234567890123456789012345678901234567890

Before:

	domain                      status         slaves
	       /device                                      runtime status
    ----------------------------------------------------------------------
    a3sp                            on               a2us
	/devices/platform/e60b0000.i2c                      suspended

After:

    domain                          status          slaves
	/device                                             runtime status
    ----------------------------------------------------------------------
    a3sp                            on              a2us
	/devices/platform/e60b0000.i2c                      suspended

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>