Fix missing ROM partition type

[kolipka]

With this fix ROM partition will be handled.
To test it:

1. In os/.config add line:
   CONFIG_FS_ROMFS=y
2. Adjust partitions, eg:

CONFIG_ARTIK053_FLASH_PART_LIST="16,48,192,32,512,2400,1536,1536,1000,400,8,512,"
CONFIG_ARTIK053_FLASH_PART_TYPE="none,ftl,none,none,none,none,none,ftl,smartfs,romfs,config,none,"
CONFIG_ARTIK053_FLASH_PART_NAME="bl1,sssro,bl2,sssfw,wlanfw,os,factory,ota,user,rom,nvram,sssrw,"

above lines change size of main user partition from 1400 * 1KB to 1000 * 1KB
and add new 400 * 1KB partition. Type is romfs.
3. call make to build image
4. prepare ROM image using genromfs
genromfs -f bin/rom.img -d /path/to/rom_fs/folder -V "NuttXBootVol"
5. in openocd/partition_map.cfg add line corresponding with point 2

user	{ "USER R/W"		0x04620000	0x000FA000  0 }
rom  	{ "ROM FS"  		0x0471A000	0x00064000  0 }

6. flash os & rom

flash_write os     ../bin/tinyara_head.bin;       \
flash_write rom    ../bin/rom.img;       \

7. mount on device
   mount -t romfs /dev/smart4rom9 /rom

[sunghan-chang]

@JunhwanPark Please review this P.R.

[heesub]

OK, this commit initializes an MTD partition of which type is 'romfs' at boot. so that it can be accessed through /dev/smartXromY. It does not affect others unless they modifies their configuration. Looks quite relevant and good to me.