Sort the SPI makefile and enforce the naming convention spi_*.c for
This change also rolls the contents of atmel_spi.h into the .c file
since there is only one user of that particular include file.
v2: - Use 'spi-' prefix instead of 'spi_' to match what seems to be
be the predominant pattern for subsystem prefixes.
- Clean up filenames in Kconfig and header comment blocks
Signed-off-by: Grant Likely <email@example.com>
Acked-by: Wolfram Sang <firstname.lastname@example.org>
Acked-by: Linus Walleij <email@example.com>