remoteproc/davinci: add the missing retval check for clk_enable()

The davinci platform is being switched to using the common clock
framework, where clk_enable() can fail. Add the return value check.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Suman Anna <s-anna@ti.com>
Reviewed-by: David Lechner <david@lechnology.com>
Reviewed-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>