genirq/proc: Add missing space separator back

The recent conversion of show_interrupts() to seq_put_decimal_ull_width()
caused a formatting regression as it drops a previosuly existing space
separator.

Add it back by unconditionally inserting a space after the interrupt
counts and removing the extra leading space from the chip name prints.

Fixes: f9ed1f7c ("genirq/proc: Use seq_put_decimal_ull_width() for decimal values")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: David Wang <00107082@163.com>
Link: https://lore.kernel.org/all/87zfldt5g4.ffs@tglx
Closes: https://lore.kernel.org/all/4ce18851-6e9f-bbe-8319-cc5e69fb45c@linux-m68k.org