MIPS: kexec: Relax memory restriction

We can rely on the system kernel and the dump capture kernel themselves in
memory usage.

Being restrictive with 512MB limit may cause kexec tool failure on some
platforms.

Tested-by: Rachel Mozes <[e-mail]>
Reported-by: Rachel Mozes <[e-mail]>
Signed-off-by: Dengcheng Zhu <[e-mail]>
Signed-off-by: Paul Burton <[e-mail]>
Patchwork: https://patchwork.linux-mips.org/patch/20568/
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]

arch/mips/include/asm/kexec.h

···
 #include <asm/stacktrace.h>
 
 /* Maximum physical address we can use pages from */
-#define KEXEC_SOURCE_MEMORY_LIMIT (0x20000000)
+#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
 /* Maximum address we can reach in physical address mode */
-#define KEXEC_DESTINATION_MEMORY_LIMIT (0x20000000)
+#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
  /* Maximum address we can use for the control code buffer */
-#define KEXEC_CONTROL_MEMORY_LIMIT (0x20000000)
+#define KEXEC_CONTROL_MEMORY_LIMIT (-1UL)
 /* Reserve 3*4096 bytes for board-specific info */
 #define KEXEC_CONTROL_PAGE_SIZE (4096 + 3*4096)