bus: mvebu-mbus: use %pa to print phys_addr_t

A recent change to the mbus driver added a warning printk that
prints a phys_addr_t using the %x format string, which fails in
case we build with 64-bit phys_addr_t:

drivers/bus/mvebu-mbus.c: In function 'mvebu_mbus_get_dram_win_info':
drivers/bus/mvebu-mbus.c:975:9: error: format '%x' expects argument of type 'unsigned int', but argument 2 has type 'phys_addr_t {aka long long unsigned int}' [-Werror=format=]

This uses the special %pa format string instead, so we always
print the correct type.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: f2900ace ("bus: mvebu-mbus: provide api for obtaining IO and DRAM window information")
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>