[ios/arm64] - fix bt keyboard cursor keys when compiled for 64bit arm

fix bt cursor keys for 64bit ios - i knew my offset shit was wrong ;)

Just in case we will accept the PR from linusyang at one point for beeing able to compile for ios 64bit - this is the correct bt keyboard cursor key thingy.

tested on ios7arm64 (xbmc 32bit), ios7arm64 (xbmc 64bit), ios6arm32 (xbmc 32bit), ios5arm32 (xbmc 32bit).

Its all about NSInteger beeing 32bit when compiled for arm32 and 64bit when compiled for arm64.

This can be G+1 material - just don't wanna loose the findings ...