x86: Convert arch_fsp_init() to use events

x86: Convert arch_fsp_init() to use events

Convert this to use events instead of calling a function directly in the
init sequence.

Rename it to arch_fsp_init_f() to distinguish it from the one that happens
after relocation.

For FSPv2 nothing needs to be done here, so drop the empty function.

Signed-off-by: Simon Glass <sjg@chromium.org>