Add spi_nbyte_program as generic function to the SPI layer

Corresponding to flashrom svn r583.

Signed-off-by: Paul Fox <pgf@laptop.org>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/flash.h b/flash.h
index 88df409..2bf4462 100644
--- a/flash.h
+++ b/flash.h
@@ -757,6 +757,7 @@
 uint8_t spi_read_status_register(void);
 int spi_disable_blockprotect(void);
 void spi_byte_program(int address, uint8_t byte);
+int spi_nbyte_program(int address, uint8_t *bytes, int len);
 int spi_nbyte_read(int address, uint8_t *bytes, int len);
 int spi_aai_write(struct flashchip *flash, uint8_t *buf);
 uint32_t spi_get_valid_read_addr(void);