Add support for Atmel's AT25F series of SPI flash chips

This adds support for the following chips:
 - AT25F512, AT25F512A, AT25F512B
 - AT25F1024, AT25F1024A
 - AT25F2048
 - AT25F4096

Besides the definitions of the the chips in flashchips.c this includes
- a dedicated probing method (probe_spi_at25f)
- pretty printing methods (spi_prettyprint_status_register_at25f*), and
- unlocking methods (spi_disable_blockprotect_at25f*)

Corresponding to flashrom svn r1637.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/chipdrivers.h b/chipdrivers.h
index 04ffda6..f0223ae 100644
--- a/chipdrivers.h
+++ b/chipdrivers.h
@@ -38,6 +38,7 @@
 int probe_spi_rems(struct flashctx *flash);
 int probe_spi_res1(struct flashctx *flash);
 int probe_spi_res2(struct flashctx *flash);
+int probe_spi_at25f(struct flashctx *flash);
 int spi_write_enable(struct flashctx *flash);
 int spi_write_disable(struct flashctx *flash);
 int spi_block_erase_20(struct flashctx *flash, unsigned int addr, unsigned int blocklen);
@@ -68,13 +69,19 @@
 int spi_prettyprint_status_register_amic_a25l032(struct flashctx *flash);
 int spi_prettyprint_status_register_at25df(struct flashctx *flash);
 int spi_prettyprint_status_register_at25df_sec(struct flashctx *flash);
+int spi_prettyprint_status_register_at25f(struct flashctx *flash);
+int spi_prettyprint_status_register_at25f512a(struct flashctx *flash);
 int spi_prettyprint_status_register_at25f512b(struct flashctx *flash);
+int spi_prettyprint_status_register_at25f4096(struct flashctx *flash);
 int spi_prettyprint_status_register_at25fs010(struct flashctx *flash);
 int spi_prettyprint_status_register_at25fs040(struct flashctx *flash);
 int spi_prettyprint_status_register_at26df081a(struct flashctx *flash);
 int spi_disable_blockprotect_at25df(struct flashctx *flash);
 int spi_disable_blockprotect_at25df_sec(struct flashctx *flash);
+int spi_disable_blockprotect_at25f(struct flashctx *flash);
+int spi_disable_blockprotect_at25f512a(struct flashctx *flash);
 int spi_disable_blockprotect_at25f512b(struct flashctx *flash);
+int spi_disable_blockprotect_at25f4096(struct flashctx *flash);
 int spi_disable_blockprotect_at25fs010(struct flashctx *flash);
 int spi_disable_blockprotect_at25fs040(struct flashctx *flash);
 int spi_prettyprint_status_register_s33(struct flashctx *flash);