hw: introduce kernel/user address space split

* introduces central memory map for core/kernel
* on 32-bit platforms the kernel/core starts at 0x80000000
* on 64-bit platforms the kernel/core starts at 0xffffffc000000000
* mark kernel/core mappings as global ones (tagged TLB)
* move the exception vector to begin of core's binary,
  thereby bootstrap knows from where to map it appropriately
* do not map boot modules into core anymore
* constrain core's virtual heap memory area
* differentiate in between user's and core's main thread's UTCB,
  which now resides inside the kernel segment

Ref #2091

repos/base-nova/src/kernel/nova/target.mk

@@ -23,10 +23,12 @@ CC_OPT          += -pipe \
                    -fno-asynchronous-unwind-tables -std=gnu++0x 
 CC_OPT_PIC      :=
 ifeq ($(filter-out $(SPECS),32bit),)
+override CC_MARCH = -m32
 CC_WARN         += -Wframe-larger-than=96
 CC_OPT          += -mpreferred-stack-boundary=2 -mregparm=3
 else
 ifeq ($(filter-out $(SPECS),64bit),)
+override CC_MARCH = -m64
 CC_WARN         += -Wframe-larger-than=240
 CC_OPT          += -mpreferred-stack-boundary=4 -mcmodel=kernel -mno-red-zone
 else