[2.6 patch] prism54: misc cleanups

This patch makes some functions in prism54 that are only required locally static. As a side effect it turned out that the mgt_unlatch_all function was completely unused, and it's therefore #if 0'ed. I also considered moving display_buffer as static inline into islpci_mgt.h, but I wasn't 100%

[2.6 patch] prism54: misc cleanups

This patch makes some functions in prism54 that are only required locally static. As a side effect it turned out that the mgt_unlatch_all function was completely unused, and it's therefore #if 0'ed. I also considered moving display_buffer as static inline into islpci_mgt.h, but I wasn't 100%