kbuild: Allow drivers to fit src/drivers/[X]/[Y]/ scheme

Reorder drivers to fit src/drivers/[X]/[Y]/ scheme to make
them pluggable.

Also, fix up the following driver subdirectories by switching
to the src/drivers/[X]/[Y]/ scheme as these are hard requirements
for the main change:

* drivers/intel
* drivers/pc80
* drivers/dec

Change-Id: I455d3089a317181d5b99bf658df759ec728a5f6b
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: https://review.coreboot.org/14047
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/include/pc80/mc146818rtc.h b/src/include/pc80/mc146818rtc.h
index 38f2ad0..f5630c5 100644
--- a/src/include/pc80/mc146818rtc.h
+++ b/src/include/pc80/mc146818rtc.h
@@ -179,7 +179,7 @@
 unsigned read_option_lowlevel(unsigned start, unsigned size, unsigned def);
 
 #else /* defined(__ROMCC__) */
-#include <drivers/pc80/mc146818rtc_early.c>
+#include <drivers/pc80/rtc/mc146818rtc_early.c>
 #endif /* !defined(__ROMCC__) */
 #define read_option(name, default) read_option_lowlevel(CMOS_VSTART_ ##name, CMOS_VLEN_ ##name, (default))