16 minors per MMC block device are required to boot Rinato (Gear 2)
board because up to 15 partitions are used.

With default 8 minors booting failed with:
[    1.329092] mmcblk0: mmc0:0001 F5X5MA 3.64 GiB
[    1.329448] mmcblk0boot0: mmc0:0001 F5X5MA partition 1 4.00 MiB
[    1.329627] mmcblk0boot1: mmc0:0001 F5X5MA partition 2 4.00 MiB
[    1.329808] mmcblk0rpmb: mmc0:0001 F5X5MA partition 3 512 KiB
[    1.335717]  mmcblk0: p1 p2 p3 p4 p5 p6 p7
[    1.436553] Waiting for root device /dev/mmcblk0p15...

while the correct list of partitions on mmcblk0 for Gear 2 is:
[    1.436651]  mmcblk0: p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 p11 p12 p13 p14 p15
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>