gallium: list use inline function to avoid macro shot coming

gallium: list use inline function to avoid macro shot coming

Macro can lead to hard to debug list bugs. For instance consider
the following :
LIST_ADD(item, list->prev)
3 instruction of the macro became :
(list->prev)->next->prev = item
which is equivalent to :
list->prev = item
Thus list prev field changes and next instruction in the macro
(list->prev)->next = item
became :
item->next = item
And you endup with list corruption, other case lead to similar
list corruption. Inline function are not affected by this short
coming

Signed-off-by: Jerome Glisse <jglisse@redhat.com>