This commit ensures that all backing memory allocated for the Guest CPU
is aligned to 256 bytes. This due to how gpu memory works and the heavy
constraints it has in the alignment of physical memory.

Instead of storing all block width, height and depths in their shifted
form:

block_width = 1U << block_shift;

Store them like they are provided by the emulated hardware (their
block_shift form). This way we can avoid doing the costly
Common::AlignUp operation to align texture sizes and drop CPU integer
divisions with bitwise logic (defined in Common::AlignBits).

This will be used in a following change to svcArbitrateLock() and
svcArbitrateUnlock()

Aligning on 4KB pages isn't a Switch-specific thing, so this can be
moved to common so it can be used with other things as well.

Uses the C++17 inline variable variants