cpu/x86/Kconfig: Remove unused CPU_ADDR_BITS

Change-Id: I88f62c18b814ac0ddd356944359e727d6e3bba5a
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58688
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Mariusz Szafrański <mariuszx.szafranski@intel.com>

src/soc/amd/picasso/Kconfig

@@ -200,10 +200,6 @@ config RAMBASE
 	hex
 	default 0x10000000
 
-config CPU_ADDR_BITS
-	int
-	default 48
-
 config MMCONF_BASE_ADDRESS
 	default 0xF8000000