Improve SPI status register pretty printing

- Move all functions related to SPI status registers to a new file
   spi25_statusreg.c. This includes the generic as well as the
   SST-specific functions from spi25.c and the chip-specific functions
   from a25.c and at25.c.
 - introduce helper functions
    * spi_prettyprint_status_register_hex()
    * spi_prettyprint_status_register_bpl()
    * spi_prettyprint_status_register_plain()
   Use the latter on every compatible flash chip that has no better printlock
   function set and get rid of the implicit pretty printing in the SPI probing
   functions.
 - remove
    * spi_prettyprint_status_register_common()
    * spi_prettyprint_status_register_amic_a25lq032() because it can be fully
      substituted with spi_prettyprint_status_register_amic_a25l032().
    * spi_prettyprint_status_register() (old switch, no longer needed)
 - promote and export
    * spi_prettyprint_status_register_amic_a25l05p() as spi_prettyprint_status_register_default_bp1().
    * spi_prettyprint_status_register_amic_a25l40p() as spi_prettyprint_status_register_default_bp2().
    * spi_prettyprint_status_register_st_m25p() as spi_prettyprint_status_register_default_bp3().
 - add #define TEST_BAD_REW and use it for a number of Atmel chips which
   had only TEST_BAD_READ set even though they dont have erasers or a write
   function set.

Corresponding to flashrom svn r1634.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

flash.h

@@ -188,6 +188,7 @@ struct flashctx {
 #define TEST_BAD_READ	(1 << 5)
 #define TEST_BAD_ERASE	(1 << 6)
 #define TEST_BAD_WRITE	(1 << 7)
+#define TEST_BAD_REW	(TEST_BAD_READ | TEST_BAD_ERASE | TEST_BAD_WRITE)
 #define TEST_BAD_PREW	(TEST_BAD_PROBE | TEST_BAD_READ | TEST_BAD_ERASE | TEST_BAD_WRITE)
 #define TEST_BAD_MASK	0xf0