LoongArch: Consolidate early_ioremap()/ioremap_prot()

LoongArch: Consolidate early_ioremap()/ioremap_prot()

1. Use phys_addr_t instead of u64, which can work for both 32/64 bits.
2. Check whether the input physical address is above TO_PHYS_MASK (and
   return NULL if yes) for the DMW version.

Note: In theory early_ioremap() also need the TO_PHYS_MASK checking, but
the UEFI BIOS pass some DMW virtual addresses.

Cc: stable@vger.kernel.org
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>