arm64: mm: drop unused __pa(__idmap_text_start)

x5 is not used in the following map_memory. Instead,
__pa(__idmap_text_start) is stored in x3 which is used later.

Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210518101405.1048860-4-aisheng.dong@nxp.com
Signed-off-by: Will Deacon <will@kernel.org>

arch/arm64/kernel/head.S

@@ -354,7 +354,6 @@ SYM_FUNC_START_LOCAL(__create_page_tables)
 #endif
 1:
 	ldr_l	x4, idmap_ptrs_per_pgd
-	mov	x5, x3				// __pa(__idmap_text_start)
 	adr_l	x6, __idmap_text_end		// __pa(__idmap_text_end)
 
 	map_memory x0, x1, x3, x6, x7, x3, x4, x10, x11, x12, x13, x14