ghost n goblins: redish screen after pausing and resuming the game

[herraa1]

Tested on latest (main branch) tnCart firmware for WonderTANG! 1.02d (it happens too in 1.01c and 2.00 WonderTANG! revisions).

How to reproduce:

• Load the Ghost and Goblins demo or the official game
• start your play
• pause the game with F1
• then resume the game with F1
• you can play again the game but the screen will remain in a "red-ish" tone until you get killed (and the overall progress screen is shown again, which "fixes" the color).

This does not happen for example when playing the game on a MSXVR (a supported configuration for the official game).

It looks that the V9990 implementation is missing something here.

[herraa1]

This is a sample screen where the problem can be seen.