pcmcia: soc_common: Handle return value of clk_prepare_enable

clk_prepare_enable() can fail here and we must check its return value.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
CC: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>