In the Linux kernel, the ST-Ericsson NovaThor U8500 SoC is barely
ever mentioned under the "NovaThor" name, more common are names like
U8500, Ux500, ST-Ericsson, STE, ...
Let's rename the kernel package to linux-postmarketos-stericsson
to make that more clear. Also cleanup the APKBUILD a bit while we're
at it, HOSTCC is unneeded, remove unnecessary depends, ...