kernel: add option to build different page sizes

For the bcm2712 subtarget, there are three valid values for memory page
sizes, 4KB, 16BK, and 64KB. This commit allows users to select one from
the nconfig/menuconfig under:

Global build settings -> Kernel build options -> Page size config

Verify that each new option builds and that images boot and run with the
expected options on RPi5B.

Signed-off-by: John Audia <therealgraysky@proton.me>

config/Config-kernel.in

@@ -1488,3 +1488,64 @@ config KERNEL_WERROR
 	  and unusual warnings, or you have some architecture with problems,
 	  you may need to disable this config option in order to
 	  successfully build the kernel.
+
+config PAGESIZE
+	bool
+
+choice
+	prompt "Page size (translation granule) configuration"
+	depends on TARGET_bcm27xx_bcm2712
+	default KERNEL_ARM64_4K_PAGES
+
+	config KERNEL_ARM64_4K_PAGES
+		bool "4KB"
+		select KERNEL_ARM64_VA_BITS_48
+		help
+			This feature enables 4KB pages support.
+
+	config KERNEL_ARM64_16K_PAGES
+		bool "16KB"
+		select KERNEL_ARM64_VA_BITS_47
+		help
+			This feature enables 16KB pages support allowing only two
+			levels of page tables and faster TLB look-up. AArch32
+			emulation requires applications compiled with 16K (or a
+			multiple of 16K) aligned segments.
+
+	config KERNEL_ARM64_64K_PAGES
+		bool "64KB"
+		select KERNEL_ARM64_VA_BITS_48
+		help
+			This feature enables 64KB pages support allowing only two
+			levels of page tables and faster TLB look-up. AArch32
+			emulation requires applications compiled with 64K aligned
+			segments.
+endchoice
+
+config KERNEL_ARM64_PA_BITS_52
+	def_bool n
+
+config KERNEL_ARM64_VA_BITS_36
+	def_bool n
+
+config KERNEL_ARM64_VA_BITS_39
+	def_bool n
+
+config KERNEL_ARM64_VA_BITS_42
+	def_bool n
+
+config KERNEL_ARM64_VA_BITS_52
+	def_bool n
+
+config KERNEL_ARM64_VA_BITS_48
+	def_bool y if (KERNEL_ARM64_4K_PAGES || KERNEL_ARM64_64K_PAGES)
+	def_bool n
+
+config KERNEL_ARM64_VA_BITS_47
+	def_bool y if KERNEL_ARM64_16K_PAGES
+	def_bool n
+
+config KERNEL_ARM64_VA_BITS
+	int
+	default 48 if KERNEL_ARM64_VA_BITS_48
+	default 47 if KERNEL_ARM64_VA_BITS_47