LoongArch: Use la.pcrel instead of la.abs when it's trivially possible

Let's start to kill la.abs in preparation for the subsequent support of
the PIE kernel.

BTW, Re-tab the indention in arch/loongarch/kernel/entry.S for alignment.
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/include/asm/stackframe.h

@@ -90,7 +90,7 @@
 	.endm
 
 	.macro	set_saved_sp stackp temp temp2
-	la.abs	  \temp, kernelsp
+	la.pcrel  \temp, kernelsp
 #ifdef CONFIG_SMP
 	LONG_ADD  \temp, \temp, u0
 #endif

arch/loongarch/include/asm/uaccess.h

@@ -22,7 +22,6 @@
 extern u64 __ua_limit;
 
 #define __UA_ADDR	".dword"
-#define __UA_LA		"la.abs"
 #define __UA_LIMIT	__ua_limit
 
 /*

arch/loongarch/kernel/entry.S

@@ -20,7 +20,7 @@
 	.align	5
 SYM_FUNC_START(handle_syscall)
 	csrrd		t0, PERCPU_BASE_KS
-	la.abs	t1, kernelsp
+	la.pcrel	t1, kernelsp
 	add.d		t1, t1, t0
 	move		t2, sp
 	ld.d		sp, t1, 0

arch/loongarch/kernel/head.S

@@ -117,7 +117,7 @@ SYM_CODE_START(smpboot_entry)
 	li.w		t0, 0x00		# FPE=0, SXE=0, ASXE=0, BTE=0
 	csrwr		t0, LOONGARCH_CSR_EUEN
 
-	la.abs		t0, cpuboot_data
+	la.pcrel	t0, cpuboot_data
 	ld.d		sp, t0, CPU_BOOT_STACK
 	ld.d		tp, t0, CPU_BOOT_TINFO
 

arch/loongarch/mm/tlbex.S

@@ -24,8 +24,7 @@
 	move		a0, sp
 	REG_S		a2, sp, PT_BVADDR
 	li.w		a1, \write
-	la.abs		t0, do_page_fault
-	jirl		ra, t0, 0
+	bl		do_page_fault
 	RESTORE_ALL_AND_RET
 	SYM_FUNC_END(tlb_do_page_fault_\write)
 	.endm