You may be missing the kernel headers package: pacman -S linux-headers
That should get you the appropriate kernel headers.
When you press /, it says
Enter CONFIG_ (sub)string to search for (with or without "CONFIG_")
which means it's looking for the names of the options, not the labels of the options.
With Linux 3.3, I found your option using grep...
$ find . -name Kconfig -exec grep 'config.*PCI' {} + | grep DMA
./drivers/ide/Kconfig:config BLK_DEV_IDEDMA_PCI
And then opened the file ./drivers/ide/Kconfig to see more information
config BLK_DEV_IDEDMA_PCI
bool
select BLK_DEV_IDEPCI
select BLK_DEV_IDEDMA_SFF
Since it doesn't have a tristate or bool line like the others, that suggests it doesn't appear in the menu.
Searching in the same file for BLK_DEV_IDEDMA_PCI, you can see lots of entries that refer to it, e.g.
config BLK_DEV_AMD74XX
tristate "AMD and nVidia IDE support"
depends on !ARM
select IDE_TIMINGS
select BLK_DEV_IDEDMA_PCI
So it looks like you're not supposed to enable DMA explicitly: the drivers that need DMA will enable it automatically.
Best Answer
Your trouble is relative to this patch [x86: Force asm-goto].
You need to install a gcc version >= 4.5