OMAP: hwmod: fix build break on non-OMAP4 multi-OMAP2 builds

Builds for multi-OMAP2 (e.g., OMAP2420 with OMAP2430) with
CONFIG_ARCH_OMAP4=n fail with the following errors:

arch/arm/mach-omap2/built-in.o: In function `_enable_module':
arch/arm/mach-omap2/omap_hwmod.c:701: undefined reference to `omap4_cminst_module_enable'
arch/arm/mach-omap2/built-in.o: In function `_disable_module':
arch/arm/mach-omap2/omap_hwmod.c:726: undefined reference to `omap4_cminst_module_disable'
arch/arm/mach-omap2/built-in.o: In function `_wait_target_disable':
arch/arm/mach-omap2/omap_hwmod.c:1179: undefined reference to `omap4_cminst_wait_module_idle'

This is probably due to the preprocessor directives in
arch/arm/plat-omap/include/plat/cpu.h that convert some cpu_is_omap*()
expressions from preprocessor directives into something that is only
resolvable during runtime, if multiple OMAP2 build targets are
selected.

Thanks to Tony Lindgren <tony@atomide.com> for reporting.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/cminst44xx.h

@@ -18,13 +18,36 @@ extern void omap4_cminst_clkdm_force_sleep(u8 part, s16 inst, u16 cdoffs);
 extern void omap4_cminst_clkdm_force_wakeup(u8 part, s16 inst, u16 cdoffs);
 
 extern int omap4_cminst_wait_module_ready(u8 part, u16 inst, s16 cdoffs, u16 clkctrl_offs);
-extern int omap4_cminst_wait_module_idle(u8 part, u16 inst, s16 cdoffs, u16 clkctrl_offs);
+
+# ifdef CONFIG_ARCH_OMAP4
+extern int omap4_cminst_wait_module_idle(u8 part, u16 inst, s16 cdoffs,
+					 u16 clkctrl_offs);
 
 extern void omap4_cminst_module_enable(u8 mode, u8 part, u16 inst, s16 cdoffs,
 				       u16 clkctrl_offs);
 extern void omap4_cminst_module_disable(u8 part, u16 inst, s16 cdoffs,
 					u16 clkctrl_offs);
 
+# else
+
+static inline int omap4_cminst_wait_module_idle(u8 part, u16 inst, s16 cdoffs,
+					u16 clkctrl_offs)
+{
+	return 0;
+}
+
+static inline void omap4_cminst_module_enable(u8 mode, u8 part, u16 inst,
+				s16 cdoffs, u16 clkctrl_offs)
+{
+}
+
+static inline void omap4_cminst_module_disable(u8 part, u16 inst, s16 cdoffs,
+				 u16 clkctrl_offs)
+{
+}
+
+# endif
+
 /*
  * In an ideal world, we would not export these low-level functions,
  * but this will probably take some time to fix properly