m25p80: change cur_addr to 32 bit integer

m25p80: change cur_addr to 32 bit integer

The maximum amount of storage that can be addressed by the m25p80 command
set is 4 GiB.  However, cur_addr is currently a 64-bit integer.  To avoid
further problems related to sign extension of signed 32-bit integer
expressions, change cur_addr to a 32 bit integer.  Preserve migration
format by adding a dummy 4-byte field in place of the (big-endian)
high four bytes in the formerly 64-bit cur_addr field.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1467138270-32481-5-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>