sh: Restrict DSP support to specific CPUs.

Not all CPUs support the DSP, and this leads to problems when mixing
and matching CPU types and DSP opcodes. Fix this up by only allowing
CONFIG_SH_DSP to be enabled for the CPUs that explicitly have such a
block.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/mm/Kconfig

@@ -27,6 +27,7 @@ config CPU_SH4A
 config CPU_SH4AL_DSP
 	bool
 	select CPU_SH4A
+	select CPU_HAS_DSP
 
 config CPU_SUBTYPE_ST40
 	bool
@@ -102,6 +103,7 @@ config CPU_SUBTYPE_SH7710
 	bool "Support SH7710 processor"
 	select CPU_SH3
 	select CPU_HAS_IPR_IRQ
+	select CPU_HAS_DSP
 	help
 	  Select SH7710 if you have a SH3-DSP SH7710 CPU.
 
@@ -109,6 +111,7 @@ config CPU_SUBTYPE_SH7712
 	bool "Support SH7712 processor"
 	select CPU_SH3
 	select CPU_HAS_IPR_IRQ
+	select CPU_HAS_DSP
 	help
 	  Select SH7712 if you have a SH3-DSP SH7712 CPU.