LoongArch's include/asm/addrspace.h uses SZ_32M and SZ_16K, so add
<linux/sizes.h> to provide those macros to prevent build errors:

In file included from ../arch/loongarch/include/asm/io.h:11,
                 from ../include/linux/io.h:13,
                 from ../include/linux/io-64-nonatomic-lo-hi.h:5,
                 from ../drivers/cxl/pci.c:4:
../include/asm-generic/io.h: In function 'ioport_map':
../arch/loongarch/include/asm/addrspace.h:124:25: error: 'SZ_32M' undeclared (first use in this function); did you mean 'PS_32M'?
  124 | #define PCI_IOSIZE      SZ_32M
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>