Print an error message on read errors and abort instead of proceeding anyway

Improve error checking in file write, chip read and chip verify.
Refactor the read routines a bit to split reading from file writing.

Log for a failed read:
[...]
Found chip "Winbond W25x16" (2048 KB, SPI) at physical address
0xffe00000.
Reading flash... Invalid OPCODE 0x03
Read operation failed!
FAILED.

Corresponding to flashrom svn r1079.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stephen Kou <stephen@hyarros.com>
diff --git a/cli_classic.c b/cli_classic.c
index 8279cc2..a81a5a7 100644
--- a/cli_classic.c
+++ b/cli_classic.c
@@ -417,7 +417,7 @@
 				exit(1);
 			}
 			printf("Please note that forced reads most likely contain garbage.\n");
-			return read_flash(flashes[0], filename);
+			return read_flash_to_file(flashes[0], filename);
 		}
 		// FIXME: flash writes stay enabled!
 		programmer_shutdown();