clk: tegra: Fix typos around clearing PLLE bits during enable

While enabling PLLE on both Tegra114 and Tegra210, we should be clearing
PLLE_MISC_VREG_BG_CTRL_MASK and PLLE_MISC_VREG_CTRL_MASK not setting
them. This patch fixes both places where we incorrectly set instead of
cleared those bits.

Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>