spi: qup: fix 64-bit build warning

On 64-bit systems, pointers are wider than 'int' variables,
so we get a warning about a cast between them:

drivers/spi/spi-qup.c:1060:23: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]

This changes the code to use the correct uintptr_t cast.

Fixes: 4d023737 ("spi: qup: Fix QUP version identify method")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>