ARM: 7737/1: fix kernel decompressor compilation error with CONFIG_DEBUG_SEMIHOSTING

Selecting this option produces:

  AS      arch/arm/boot/compressed/debug.o
arch/arm/boot/compressed/debug.S:4:33: fatal error: mach/debug-macro.S: No such file or directory
compilation terminated.
make[3]: *** [arch/arm/boot/compressed/debug.o] Error 1

The semihosting support cannot be modelled into a senduart macro as
it requires memory space for argument passing.  So the
CONFIG_DEBUG_LL_INCLUDE may not have any sensible value and the include
directive should be omitted.

While at it, let's add proper semihosting output support to the
decompressor.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/boot/compressed/debug.S

 #include <linux/linkage.h>
 #include <asm/assembler.h>
 
+#ifndef CONFIG_DEBUG_SEMIHOSTING
+
 #include CONFIG_DEBUG_LL_INCLUDE
 
 ENTRY(putc)
@@ -10,3 +12,29 @@ ENTRY(putc)
 	busyuart r3, r1
 	mov	 pc, lr
 ENDPROC(putc)
+
+#else
+
+ENTRY(putc)
+	adr	r1, 1f
+	ldmia	r1, {r2, r3}
+	add	r2, r2, r1
+	ldr	r1, [r2, r3]
+	strb	r0, [r1]
+	mov	r0, #0x03		@ SYS_WRITEC
+   ARM(	svc	#0x123456	)
+ THUMB(	svc	#0xab		)
+	mov	pc, lr
+	.align	2
+1:	.word	_GLOBAL_OFFSET_TABLE_ - .
+	.word	semi_writec_buf(GOT)
+ENDPROC(putc)
+
+	.bss
+	.global	semi_writec_buf
+	.type   semi_writec_buf, %object
+semi_writec_buf:
+	.space	4
+	.size	semi_writec_buf, 4
+
+#endif