drm/amd/display: Assign normalized_pix_clk when color depth = 14

[WHY & HOW]
A warning message "WARNING: CPU: 4 PID: 459 at ... /dc_resource.c:3397
calculate_phy_pix_clks+0xef/0x100 [amdgpu]" occurs because the
display_color_depth == COLOR_DEPTH_141414 is not handled. This is
observed in Radeon RX 6600 XT.

It is fixed by assigning pix_clk * (14 * 3) / 24 - same as the rests.

Also fixes the indentation in get_norm_pix_clk.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>