SPARC: improve fatal log

The fatal log now contains
- Trap type in human readable representation
- Integer registers visible to the program when trap was taken
- Special register values such as PC and PSR
- Backtrace with PC and SP

If CONFIG_EXTRA_EXCEPTION_INFO is enabled, then all the above is
logged. If not, only the special registers are logged.

The format is inspired by the GRMON debug monitor and TSIM simulator.
A quick guide on how to use the values is in fatal.c.

It now looks like this:

E: tt = 0x02, illegal_instruction
E:
E:       INS        LOCALS     OUTS       GLOBALS
E:   0:  00000000   f3900fc0   40007c50   00000000
E:   1:  00000000   40004bf0   40008d30   40008c00
E:   2:  00000000   40004bf4   40008000   00000003
E:   3:  40009158   00000000   40009000   00000002
E:   4:  40008fa8   40003c00   40008fa8   00000008
E:   5:  40009000   f3400fc0   00000000   00000080
E:   6:  4000a1f8   40000050   4000a190   00000000
E:   7:  40002308   00000000   40001fb8   000000c1
E:
E: psr: f30000c7   wim: 00000008   tbr: 40000020   y: 00000000
E:  pc: 4000a1f4   npc: 4000a1f8
E:
E:       pc         sp
E:  #0   4000a1f4   4000a190
E:  #1   40002308   4000a1f8
E:  #2   40003b24   4000a258

Signed-off-by: Martin Åberg <martin.aberg@gaisler.com>

include/arch/sparc/arch.h

@@ -102,11 +102,13 @@ static inline uint32_t arch_k_cycle_get_32(void)
 
 
 struct __esf {
+	uint32_t out[8];
+	uint32_t global[8];
+	uint32_t psr;
 	uint32_t pc;
 	uint32_t npc;
-	uint32_t psr;
+	uint32_t wim;
 	uint32_t tbr;
-	uint32_t sp;
 	uint32_t y;
 };