drm/amdgpu:mark aqua_vanjaram_reg_init.c function as static

A few newly added global functions have no prototype, which causes warnings:

drivers/gpu/drm/amd/amdgpu/aqua_vanjaram_reg_init.c:169:5: error: no previous prototype for 'aqua_vanjaram_select_scheds' [-Werror=missing-prototypes]
drivers/gpu/drm/amd/amdgpu/aqua_vanjaram_reg_init.c:310:5: error: no previous prototype for '__aqua_vanjaram_get_xcc_per_xcp' [-Werror=missing-prototypes]
drivers/gpu/drm/amd/amdgpu/aqua_vanjaram_reg_init.c:337:5: error: no previous prototype for '__aqua_vanjaram_get_xcp_ip_info' [-Werror=missing-prototypes]
drivers/gpu/drm/amd/amdgpu/aqua_vanjaram_reg_init.c:593:5: error: no previous prototype for 'aqua_vanjaram_get_xcp_ip_details' [-Werror=missing-prototypes]

There are no callers from other files, so just mark them as 'static'.

Fixes: cd7d8400 ("drm/amdgpu: add partition schedule for GC(9, 4, 3)")
Fixes: 9cb18287 ("drm/amdgpu: Add SOC partition funcs for GC v9.4.3")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>