x86/kernel/cpu/cyrix.c now needs to include <linux/isa-dma.h> since the
'isa_dma_bridge_buggy' variable was moved to it.
Fixes this build error:
../arch/x86/kernel/cpu/cyrix.c: In function ‘init_cyrix’:
../arch/x86/kernel/cpu/cyrix.c:277:17: error: ‘isa_dma_bridge_buggy’ undeclared (first use in this function)
277 | isa_dma_bridge_buggy = 2;