ARM: at91: move platform-specific asm-offset.h to arch/arm/mach-at91

<generated/at91_pm_data-offsets.h> is only generated and included by
arch/arm/mach-at91/, so it does not need to reside in the globally
visible include/generated/.

I renamed it to arch/arm/mach-at91/pm_data-offsets.h since the prefix
'at91_' is just redundant in mach-at91/.

My main motivation of this change is to avoid the race condition for
the parallel build (-j) when CONFIG_IKHEADERS is enabled.

When it is enabled, all the headers under include/ are archived into
kernel/kheaders_data.tar.xz and exposed in the sysfs.

In the parallel build, we have no idea in which order files are built.

 - If at91_pm_data-offsets.h is built before kheaders_data.tar.xz,
   the header will be included in the archive. Probably nobody will
   use it, but it is harmless except that it will increase the archive
   size needlessly.

 - If kheaders_data.tar.xz is built before at91_pm_data-offsets.h,
   the header will not be included in the archive. However, in the next
   build, the archive will be re-generated to include the newly-found
   at91_pm_data-offsets.h. This is not nice from the build system point
   of view.

 - If at91_pm_data-offsets.h and kheaders_data.tar.xz are built at the
   same time, the corrupted header might be included in the archive,
   which does not look nice either.

This commit fixes the race.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Link: https://lore.kernel.org/r/20190823024346.591-1-yamada.masahiro@socionext.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

arch/arm/mach-at91/.gitignore

+pm_data-offsets.h

arch/arm/mach-at91/Makefile

@@ -19,9 +19,10 @@ ifeq ($(CONFIG_PM_DEBUG),y)
 CFLAGS_pm.o += -DDEBUG
 endif
 
-include/generated/at91_pm_data-offsets.h: arch/arm/mach-at91/pm_data-offsets.s FORCE
+$(obj)/pm_data-offsets.h: $(obj)/pm_data-offsets.s FORCE
 	$(call filechk,offsets,__PM_DATA_OFFSETS_H__)
 
-arch/arm/mach-at91/pm_suspend.o: include/generated/at91_pm_data-offsets.h
+$(obj)/pm_suspend.o: $(obj)/pm_data-offsets.h
 
 targets += pm_data-offsets.s
+clean-files += pm_data-offsets.h

arch/arm/mach-at91/pm_suspend.S

@@ -10,7 +10,7 @@
 #include <linux/linkage.h>
 #include <linux/clk/at91_pmc.h>
 #include "pm.h"
-#include "generated/at91_pm_data-offsets.h"
+#include "pm_data-offsets.h"
 
 #define	SRAMC_SELF_FRESH_ACTIVE		0x01
 #define	SRAMC_SELF_FRESH_EXIT		0x00