clk: Don't try to enable critical clocks if prepare failed

The following traceback is seen if a critical clock fails to prepare.

bcm2835-clk 3f101000.cprman: plld: couldn't lock PLL
------------[ cut here ]------------
Enabling unprepared plld_per
WARNING: CPU: 1 PID: 1 at drivers/clk/clk.c:1014 clk_core_enable+0xcc/0x2c0
...
Call trace:
 clk_core_enable+0xcc/0x2c0
 __clk_register+0x5c4/0x788
 devm_clk_hw_register+0x4c/0xb0
 bcm2835_register_pll_divider+0xc0/0x150
 bcm2835_clk_probe+0x134/0x1e8
 platform_drv_probe+0x50/0xa0
 really_probe+0xd4/0x308
 driver_probe_device+0x54/0xe8
 device_driver_attach+0x6c/0x78
 __driver_attach+0x54/0xd8
...

Check return values from clk_core_prepare() and clk_core_enable() and
bail out if any of those functions returns an error.

Cc: Jerome Brunet <jbrunet@baylibre.com>
Fixes: 99652a46

 ("clk: migrate the count of orphaned clocks at init")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lkml.kernel.org/r/20191225163429.29694-1-linux@roeck-us.net
Signed-off-by: Stephen Boyd <sboyd@kernel.org>