x86/cyrix: include header linux/isa-dma.h

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;

Fixes: abb4970a ("PCI: Move isa_dma_bridge_buggy out of asm/dma.h")
Link: https://lore.kernel.org/r/20220725202224.29269-1-rdunlap@infradead.orgSigned-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Stafford Horne <shorne@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org

arch/x86/kernel/cpu/cyrix.c

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/bitops.h>
 #include <linux/delay.h>
+#include <linux/isa-dma.h>
 #include <linux/pci.h>
 #include <asm/dma.h>
 #include <linux/io.h>