ARM: OMAP: Fix warning in clock.c

Fix warning:

arch/arm/mach-omap1/clock.c: In function
'omap1_clk_enable_generic':
arch/arm/mach-omap1/clock.c:499: warning: 'return' with no
value, in function returning non-void

Signed-off-by: Dirk Behme <dirk.behme_at_gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>