Normalize POST initialization function name suffixes.

The POST phase has to invoke many initialization functions, and these
functions can have complex inter-dependencies.  Try to categorize the
functions into 4 classes:

preinit - functions called very early in POST where function ordering
    is very important and the code has limited access to other
    interfaces.

init - functions that initialize internal interfaces and standard
    external interfaces.  This code is generally not dependent on
    particular hardware and typically does not communicate directly
    with any hardware devices.

setup - functions which access hardware or are dependent on particular
    hardware or platform devices.

prepboot - functions that finalize internal interfaces and that
    prepare for the boot phase.

This patch attempts to normalize the suffixes - functions that used
_init(), _setup(), _finalize(), or similar that did not follow the
above pattern were renamed.  Other than function name changes, there
should be no code impact to this patch.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/vgasrc/clext.h b/vgasrc/clext.h
index 78dba01..efc98b9 100644
--- a/vgasrc/clext.h
+++ b/vgasrc/clext.h
@@ -17,6 +17,6 @@
 int clext_set_mode(struct vgamode_s *vmode_g, int flags);
 struct bregs;
 void clext_1012(struct bregs *regs);
-int clext_init(void);
+int clext_setup(void);
 
 #endif // clext.h