hw/display: check frame buffer can hold blob

hw/display: check frame buffer can hold blob

Coverity reports (CID 1564769, 1564770) that we potentially overflow
by doing some 32x32 multiplies for something that ends up in a 64 bit
value. Fix this by first using stride for all lines and casting input
to uint64_t to ensure a 64 bit multiply is used.

Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20241111230040.68470-3-alex.bennee@linaro.org>