drm/i915/icl: Implement HSDIV_RATIO of MG_CLKTOP2_HSCLKCTL_PORT reg as separate divid...

drm/i915/icl: Implement HSDIV_RATIO of MG_CLKTOP2_HSCLKCTL_PORT reg as separate divider value defines

The register value of Divider Ratio for high speed divider
(hsdiv_ratio) in MG_CLKTOP2_HSCLKCTL_PORT register is not same as the
actual numerical value of the divider. So this patch implements
separate divider value defines for that field.
icl_mg_pll_find_divisors() can use these defines instead of magic
register values.

The new defines are going to be used in the next patch.

v2 (from Paulo):
 * Rebase.
 * Make it look a little more like the rest of our code.
v3 (from Paulo):
 * Make hsdiv u32 now that it's a bit field (José).

Reviewed-by: Rodrigo Vivi <[email protected]>
Reviewed-by: José Roberto de Souza <[email protected]>
Suggested-by: James Ausmus <[email protected]>
Signed-off-by: Manasi Navare <[email protected]>
Signed-off-by: Paulo Zanoni <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]