Tweak 7 inch layout a bit

* For 10-9-7 (qwerty, qwertz), keys' width are 9.0%-9.0%-9.0%
* For 10-10-7 (azerty, hebrew, spanish), keys' width are 8.5%-8.5%-8.5%
* For 11-11-{7,8} (arabic, bulgarian, nordic), keys' width are 7.6%-7.6%-7.6%
* For {11,12}-11-9 (south_slavic, east_slavic), keys' width are 7.6%-7.6%-7.363%

Change-Id: Ife4ce0ac587bd179afcfce0cb5dffb8d82fee4f1