soc/amd/stoneyridge: Remove dev_find_slot where possible

The procedure dev_find_slot has 3 main uses. To find configuration
(devicetree), to verify if a particular device is enabled at build \
time, and to get the address for PCI access while in bootblock/romstage.
The third use can be hidden by using macros defined in pci_devs.h,
making it very clear what PCI device is being accessed. replace the
temporary pointers to device used with PCI access with SOC_XXX_DEV where
XXX is the device being accessed, and remove the setting of the temporary
pointers.

BUG=b:117917136
TEST=Build grunt.

Change-Id: Ic38ea04bfcc1ccaa12937b19e9442a26d869ef11
Signed-off-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
Reviewed-on: https://review.coreboot.org/29227
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/soc/amd/stoneyridge/cpu.c

@@ -55,8 +55,8 @@ static void pre_mp_init(void)
 
 static int get_cpu_count(void)
 {
-	struct device *nb = dev_find_slot(0, HT_DEVFN);
-	return (pci_read_config16(nb, D18F0_CPU_CNT) & CPU_CNT_MASK) + 1;
+	return (pci_read_config16(SOC_NB_DEV, D18F0_CPU_CNT) & CPU_CNT_MASK)
+									+ 1;
 }
 
 static void get_smm_info(uintptr_t *perm_smbase, size_t *perm_smsize,