code: dodge PAGE_SIZE #define

Some header files, specifically for OSX and Musl libc define PAGE_SIZE to be a number
This is great except in yuzu we're using PAGE_SIZE as a variable

Specific example
`static constexpr u64 PAGE_SIZE = u64(1) << PAGE_BITS;`

PAGE_SIZE PAGE_BITS PAGE_MASK are all similar variables.
Simply deleted the underscores, and then added YUZU_ prefix

Might be worth noting that there are multiple uses in different classes/namespaces
This list may not be exhaustive

Core::Memory   12 bits (4096)
QueryCacheBase 12 bits
ShaderCache    14 bits (16384)
TextureCache   20 bits (1048576, or 1MB)

Fixes #8779