hi3518ev300: add Smitch 360 PTZ device profile (JXF23, RTL8188FU, 16M NOR) (#82)

HI3518EV300 with a JXF23 sensor and an RTL8188FU USB radio on 16 MiB NOR.
Video and Wi-Fi are working on the hardware; the motors are not yet, which the
README row records.

Finished off before merging, since the branch had sat since March:

BR2_PACKAGE_JSONFILTER is dropped, as #128 did for every other defconfig after
firmware/#2304. The repack.sh section heading that had been reworded in passing
is restored to what master has, and customizer.sh gets its missing trailing
newline. Rebased onto master, where the README row now sits alongside the
SpezVision SVI-252B entry added since.

The UBI config reference is corrected. It pointed at
scripts/ubifs/ubinize_hisilicon.cfg, which is not in the firmware tree — the
two devices using that name each ship a private copy — so the build reached
rootfs.ubifs and then failed on the missing file. It now uses the in-tree
ubinize.cfg, matching both hi3518ev200 ultimate boards; that suits the nand
repack, which passes uImage separately rather than embedding it in a volume.

This profile had never been compiled by CI before, which is why a defect this
plain survived two reviews. Both artifacts now build: NOR rootfs 6828/8192 KB,
NAND rootfs.ubi 13568/16384 KB.

README.md

@@ -59,6 +59,7 @@ RunCam WiFiLink          SSC338Q      IMX415                     NOR_16M   done
 RVi-1NCMW2028 (2.8)      HI3516EV300  SC2330    RTL8188FU_USB    NAND      testing
 Smartwares CIP-37210     HI3518EV200  OV9732    RTL8188FU_USB    NOR_16M   done
 Smartwares CIP-37210AT   T21N         JXF37     RTL8188FU_USB    NOR_16M   done
+Smitch 360 PTZ           HI3518EV300  JXF23     RTL8188FU_USB    NOR_16M   video-yes, wifi-yes, motors-no
 SpezVision SVI-252B K202 HI3516CV200  IMX323    -                NOR_8M    done
 Switcam HS303 v1         HI3518EV200  JXF22     RTL8188FU_USB    NOR_16M   done
 Switcam HS303 v2         HI3518EV200  OV9732    RTL8188EU_USB    NOR_16M   done