Combine block_erase*_en29lv640b and block_erase*_m29f400bt respectively

This patch combines two identical block and chip erase functions respectively:
 - Merge block_erase_m29f400bt and block_erase_en29lv640b into
   erase_block_shifted_jedec.
 - Merge block_erase_chip_m29f400bt and block_erase_chip_en29lv640b into
   erase_chip_block_shifted_jedec.

Leave their implementations in en29lv640b.c for now.

Corresponding to flashrom svn r1808.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/chipdrivers.h b/chipdrivers.h
index 7fe3202..ee86f83 100644
--- a/chipdrivers.h
+++ b/chipdrivers.h
@@ -147,8 +147,6 @@
 
 /* m29f400bt.c */
 int probe_m29f400bt(struct flashctx *flash);
-int block_erase_m29f400bt(struct flashctx *flash, unsigned int start, unsigned int len);
-int block_erase_chip_m29f400bt(struct flashctx *flash, unsigned int start, unsigned int len);
 int write_m29f400bt(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len);
 void protect_m29f400bt(struct flashctx *flash, chipaddr bios);
 
@@ -199,8 +197,8 @@
 
 /* en29lv640b.c */
 int probe_en29lv640b(struct flashctx *flash);
-int block_erase_en29lv640b(struct flashctx *flash, unsigned int start, unsigned int len);
-int block_erase_chip_en29lv640b(struct flashctx *flash, unsigned int start, unsigned int len);
+int erase_block_shifted_jedec(struct flashctx *flash, unsigned int start, unsigned int len);
+int erase_chip_block_shifted_jedec(struct flashctx *flash, unsigned int start, unsigned int len);
 int write_en29lv640b(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len);
 
 #endif /* !__CHIPDRIVERS_H__ */