Set NumberOfSymbols to zero

Acoording to what the spec says about the number of sybols [1]:

"This value should be zero for an image because COFF debugging
information is deprecated."

Changing as if not zero it causes problems to llvm-objcopy. This
affects only the architectures where COFF is not supported by objcopy
and where we build the PE header via assembly code.

[1] https://docs.microsoft.com/en-us/windows/win32/debug/pe-format

gnuefi/crt0-efi-aarch64.S

@@ -34,7 +34,7 @@ coff_header:
 	.short	2				// nr_sections
 	.long	0 				// TimeDateStamp
 	.long	0				// PointerToSymbolTable
-	.long	1				// NumberOfSymbols
+	.long	0				// NumberOfSymbols
 	.short	section_table - optional_header	// SizeOfOptionalHeader
 	.short	0x206				// Characteristics.
 						// IMAGE_FILE_DEBUG_STRIPPED |

gnuefi/crt0-efi-arm.S

@@ -34,7 +34,7 @@ coff_header:
 	.short	2				// nr_sections
 	.long	0 				// TimeDateStamp
 	.long	0				// PointerToSymbolTable
-	.long	1				// NumberOfSymbols
+	.long	0				// NumberOfSymbols
 	.short	section_table - optional_header	// SizeOfOptionalHeader
 	.short	0x306				// Characteristics.
 						// IMAGE_FILE_32BIT_MACHINE |

gnuefi/crt0-efi-mips64el.S

@@ -35,7 +35,7 @@ coff_header:
 	.short	2				// nr_sections
 	.long	0 				// TimeDateStamp
 	.long	0				// PointerToSymbolTable
-	.long	1				// NumberOfSymbols
+	.long	0				// NumberOfSymbols
 	.short	section_table - optional_header	// SizeOfOptionalHeader
 	.short	0x206				// Characteristics.
 						// IMAGE_FILE_DEBUG_STRIPPED |

gnuefi/crt0-efi-riscv64.S

@@ -38,7 +38,7 @@ coff_header:
 	.short	2				// nr_sections
 	.long	0 				// TimeDateStamp
 	.long	0				// PointerToSymbolTable
-	.long	1				// NumberOfSymbols
+	.long	0				// NumberOfSymbols
 	.short	section_table - optional_header	// SizeOfOptionalHeader
 	.short	0x206				// Characteristics.
 						// IMAGE_FILE_DEBUG_STRIPPED |