uml: fix processor selection

Makes UML compile on any possible processor choice. The two problems were:

*) x86 code, when 386 is selected, checks at runtime boot_cpuflags, which we
   not have.
*) 3Dnow support for memcpy() et al. does not compile currently and fixing t
   is not trivial, so simply disable it; with this change, if one selects MK
   UML compiles (while it did not).
Merged upstream.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

arch/i386/Kconfig.cpu

@@ -7,6 +7,7 @@ choice
 
 config M386
 	bool "386"
+	depends on !UML
 	---help---
 	  This is the processor type of your CPU. This information is used for
 	  optimizing purposes. In order to compile a kernel that can run on
@@ -301,7 +302,7 @@ config X86_USE_PPRO_CHECKSUM
 
 config X86_USE_3DNOW
 	bool
-	depends on MCYRIXIII || MK7 || MGEODE_LX
+	depends on (MCYRIXIII || MK7 || MGEODE_LX) && !UML
 	default y
 
 config X86_OOSTORE