ARM compressed boot : cachetype variables not initialized with ARMv7 architecture

[soutade_gmail.com]

Summary

ARMv7 architecture has severals global variables containing cache information (arm_cache_loc, arm_cache_type...). It must be initialized before any cache operation. So, it's needed to call get_cachetype_cp15() at startup. Currently, it's not the case, and cpu_idcache_wbinv_all() and cpu_l2cache_wbinv_all() doesn't properly works (or take a long time before returning).