add the ability to seek to a raw location while reading MTD partition

Change-Id: Id1563ca667c50e61cf1bb15d2cf783a50937eece
diff --git a/mtdutils/mtdutils.h b/mtdutils/mtdutils.h
index 528a5bb..45d3ebc 100644
--- a/mtdutils/mtdutils.h
+++ b/mtdutils/mtdutils.h
@@ -45,6 +45,7 @@
 MtdReadContext *mtd_read_partition(const MtdPartition *);
 ssize_t mtd_read_data(MtdReadContext *, char *data, size_t data_len);
 void mtd_read_close(MtdReadContext *);
+void mtd_read_skip_to(const MtdReadContext *, size_t offset);
 
 MtdWriteContext *mtd_write_partition(const MtdPartition *);
 ssize_t mtd_write_data(MtdWriteContext *, const char *data, size_t data_len);