kernel/configs: use .incbin directive to embed config_data.gz

kernel/configs: use .incbin directive to embed config_data.gz

This slightly optimizes the kernel/configs.c build.

bin2c is not very efficient because it converts a data file into a huge
array to embed it into a *.c file.

Instead, we can use the .incbin directive.

Also, this simplifies the code; Makefile is cleaner, and the way to get
the offset/size of the config_data.gz is more straightforward.

I used the "asm" statement in *.c instead of splitting it into *.S
because MODULE_* tags are not supported in *.S files.

I also cleaned up kernel/.gitignore; "config_data.gz" is unneeded
because the top-level .gitignore takes care of the "*.gz" pattern.

[[email protected]: v2]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Masahiro Yamada <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Alexander Popov <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Richard Guy Briggs <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>