[bzimage] Increase maximum command-line size to 0x7ff

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/arch/i386/include/bzimage.h

 #define BZI_STACK_SIZE 0x1000
 
 /** Maximum size of command line */
-#define BZI_CMDLINE_SIZE 0x100
+#define BZI_CMDLINE_SIZE 0x7ff
 
 #endif /* _BZIMAGE_H */