fastboot: sparse: resync common/image-sparse.c (part 2)

- update fastboot_okay() and fastboot_fail()

This file originally came from upstream code.

While retaining the storage abstraction feature, this is the second
set of the changes required to resync with the
  cmd_flash_mmc_sparse_img()
in the file
  aboot.c
from
  https://us.codeaurora.org/cgit/quic/la/kernel/lk/plain/app/aboot/aboot.c?h=LE.BR.1.2.1

Signed-off-by: Steve Rae <srae@broadcom.com>

include/fastboot.h

@@ -16,7 +16,7 @@
 /* The 64 defined bytes plus \0 */
 #define FASTBOOT_RESPONSE_LEN	(64 + 1)
 
-void fastboot_fail(char *response, const char *reason);
-void fastboot_okay(char *response, const char *reason);
+void fastboot_fail(const char *reason);
+void fastboot_okay(const char *reason);
 
 #endif /* _FASTBOOT_H_ */