leds: add HAS_IOMEM dependency to LEDS_BCM6328/LEDS_BCM6358

Ran into this on UML:

drivers/built-in.o: In function `bcm6328_leds_probe':
drivers/leds/leds-bcm6328.c:340: undefined reference to `devm_ioremap_resource'
drivers/built-in.o: In function `bcm6358_leds_probe':
drivers/leds/leds-bcm6358.c:173: undefined reference to `devm_ioremap_resource'
collect2: error: ld returned 1 exit status

devm_ioremap_resource() is defined only when HAS_IOMEM is selected.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: linux-leds@vger.kernel.org
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>