package/infozip: Rename HOST_CC to HOSTCC

Wrong variable name is used which can lead to build errors for the host variant:

[...] -I. -DUNIX" AS=" -c" -f unix/Makefile generic

c _match.s
make[1]: c: command not found

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>