mali_kbase: platform: dvfs: Actively set boot clocks

Previously platform initializtion would ensure that the DVFS
table had a row corresponding to the default boot clocks for
the two GPU domains and error out if this wasn't the case.

This change removes this restriction thereby allowing for
increased flexibility in the GPU's DVFS table.

Bug: 177418501
Signed-off-by: Sidath Senanayake <sidaths@google.com>
Change-Id: I220de350fb981750a9a9b87724d4ca5a0a55fa6e