[CORE] Rename vmm_guest_physical_xxx() APIs to vmm_guest_memory_xxx() APIs

The original vmm_guest_physical_xxx() APIs were meant to access guest RAM, guest ROM and guest devices but for accessing guest devices we need to be in normal VCPU context.

To simply the situation we provide vmm_guest_memory_xxx() APIs for accessing guest RAM and guest ROM only.

The vmm_guest_memory_xxx() APIs will internally use vmm_host_memory_xxx() APIs to do cacheable & bufferable access guest RAM and guest ROM.

Signed-off-by: Anup Patel <anup@brainfault.org>