Draw struct flashchip into struct flashprog_flashctx

We used to have a reference to a dynamically allocated  struct flashchip
inside the flash context. But now that we only ever allocate both in one
go, we can let go of the reference and make it a single structure.

Change-Id: I857acb1def6d133a5cbc28fc7a99b7b1a22b55e0
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/494
diff --git a/spi95.c b/spi95.c
index 70a2074..475a9dc 100644
--- a/spi95.c
+++ b/spi95.c
@@ -72,7 +72,7 @@
 		return 1;
 	}
 	memset(erased_contents, ERASED_VALUE(flash), blocklen * sizeof(uint8_t));
-	result = spi_write_chunked(flash, erased_contents, 0, blocklen, flash->chip->page_size);
+	result = spi_write_chunked(flash, erased_contents, 0, blocklen, flash->chip.page_size);
 	free(erased_contents);
 	return result;
 }