s390/decompressor: clean up and rename compressed/misc.c

Since compressed/misc.c is conditionally compiled move error reporting
code to boot/main.c. With that being done compressed/misc.c has no
"miscellaneous" functions left and is all about plain decompression
now. Rename it accordingly.

Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/boot/startup.c

@@ -1,9 +1,19 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/string.h>
 #include <asm/setup.h>
+#include <asm/sclp.h>
 #include "compressed/decompressor.h"
 #include "boot.h"
 
+void error(char *x)
+{
+	sclp_early_printk("\n\n");
+	sclp_early_printk(x);
+	sclp_early_printk("\n\n -- System halted");
+
+	disabled_wait(0xdeadbeef);
+}
+
 #ifdef CONFIG_KERNEL_UNCOMPRESSED
 unsigned long mem_safe_offset(void)
 {