x86-64: align __PHYSICAL_START, remove __KERNEL_ALIGN

Handle the misconfiguration where CONFIG_PHYSICAL_START is
incompatible with CONFIG_PHYSICAL_ALIGN.  This is a configuration
error, but one which arises easily since Kconfig doesn't have the
smarts to express the true relationship between these two variables.
Hence, align __PHYSICAL_START the same way we align LOAD_PHYSICAL_ADDR
in <asm/boot.h>.

For non-relocatable kernels, this would cause the boot to fail.

[ Impact: fix boot failures for non-relocatable kernels ]
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/include/asm/page_64_types.h

@@ -32,17 +32,9 @@
  */
 #define __PAGE_OFFSET           _AC(0xffff880000000000, UL)
 
-#define __PHYSICAL_START	CONFIG_PHYSICAL_START
-#define __KERNEL_ALIGN		0x200000
-
-/*
- * Make sure kernel is aligned to 2MB address. Catching it at compile
- * time is better. Change your config file and compile the kernel
- * for a 2MB aligned address (CONFIG_PHYSICAL_START)
- */
-#if (CONFIG_PHYSICAL_START % __KERNEL_ALIGN) != 0
-#error "CONFIG_PHYSICAL_START must be a multiple of 2MB"
-#endif
+#define __PHYSICAL_START	((CONFIG_PHYSICAL_START +	 	\
+				  (CONFIG_PHYSICAL_ALIGN - 1)) &	\
+				 ~(CONFIG_PHYSICAL_ALIGN - 1))
 
 #define __START_KERNEL		(__START_KERNEL_map + __PHYSICAL_START)
 #define __START_KERNEL_map	_AC(0xffffffff80000000, UL)